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1st Year MBBS Anatomy - Abdomen & Pelvis + Lower Limb

Complete Question Bank: LAQ | Reasoning/Applied | Short Note | Applied Reasoning | Embryology & Histology (with Labels)

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PART 1: ABDOMEN & PELVIS

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SECTION A: LONG ANSWER QUESTIONS (LAQ)

Anterior Abdominal Wall

1. Describe the inguinal canal - its formation, walls, contents, and applied anatomy
2. Describe the rectus sheath - formation, contents, and clinical significance
3. Describe the inguinal ligament and its derivatives with applied anatomy
4. Describe the layers of the anterior abdominal wall with their nerve supply and blood supply

Peritoneum

1. Describe the peritoneum - its subdivisions, reflections, and recesses. Add a note on peritoneal dialysis
2. Describe the lesser sac (omental bursa) - boundaries, communications, and clinical importance
3. Describe the greater omentum - development, blood supply, and functions (policeman of the abdomen)
4. Describe the mesenteries of the gut with their attachments and clinical significance

Stomach

1. Describe the stomach in detail - position, relations, blood supply, nerve supply, lymphatic drainage, and applied anatomy
2. Describe the blood supply of the stomach and its clinical significance (gastric ulcer, gastrectomy)

Small Intestine

1. Describe the duodenum - parts, relations, blood supply, and applied anatomy
2. Describe the jejunum and ileum - differences and applied anatomy (Meckel's diverticulum)

Large Intestine

1. Describe the colon - parts, features, blood supply, and applied anatomy
2. Describe the appendix - position, blood supply, McBurney's point, and referred pain

Liver

1. Describe the liver - surfaces, lobes, relations, blood supply, venous drainage, nerve supply, lymphatics, and applied anatomy
2. Describe the porta hepatis and structures passing through it
3. Describe the portal vein - formation, tributaries, portocaval anastomoses, and applied anatomy (portal hypertension)

Gall Bladder and Bile Duct

1. Describe the gall bladder - relations, blood supply, and applied anatomy (cholecystitis, Calot's triangle)
2. Describe the extrahepatic biliary apparatus - components, relations, and applied anatomy

Pancreas

1. Describe the pancreas - parts, relations, blood supply, and applied anatomy (pancreatitis, carcinoma head of pancreas)

Spleen

1. Describe the spleen - position, surfaces, relations, blood supply, and applied anatomy (splenomegaly, splenectomy)

Kidneys

1. Describe the kidneys - position, relations (anterior and posterior), blood supply, nerve supply, and applied anatomy
2. Describe the renal fascia (Gerota's fascia) and perinephric fat - clinical significance
3. Describe the ureter - course, relations, constrictions, blood supply, and applied anatomy (ureteric calculus)

Adrenal (Suprarenal) Glands

1. Describe the suprarenal glands - position, relations, blood supply, and applied anatomy

Aorta and IVC

1. Describe the abdominal aorta - course, branches, and applied anatomy
2. Describe the inferior vena cava - formation, tributaries, and applied anatomy

Diaphragm

1. Describe the diaphragm - attachments, openings and structures passing through, nerve supply, blood supply, and applied anatomy (hiatus hernia)

Celiac Plexus and Lumbar Plexus

1. Describe the lumbar plexus - formation, branches, and applied anatomy
2. Describe the celiac plexus - formation, distribution, and clinical significance

Male Pelvis

1. Describe the male urethra - parts, relations, sphincters, and applied anatomy (catheterization, rupture)
2. Describe the prostate gland - lobes, relations, blood supply, and applied anatomy (BPH, carcinoma)
3. Describe the urinary bladder - relations (full and empty), blood supply, nerve supply, and applied anatomy

Female Pelvis

1. Describe the uterus - position, relations, blood supply, supports, and applied anatomy (prolapse, fibroids)
2. Describe the broad ligament - contents, subdivisions, and clinical significance
3. Describe the round ligament - course, contents, and applied anatomy
4. Describe the ovary - position, relations, blood supply, lymphatics, and applied anatomy
5. Describe the fallopian tube - parts, relations, blood supply, and applied anatomy (ectopic pregnancy)
6. Describe the pelvic floor - muscles, nerve supply, and applied anatomy (perineal tear, prolapse)

Pelvic Joints and Walls

1. Describe the sacroiliac joint - type, ligaments, movements, and applied anatomy
2. Describe the pelvic walls and floor with their muscles and clinical significance

Perineum

1. Describe the ischiorectal (ischioanal) fossa - boundaries, contents, and applied anatomy (abscess, fistula-in-ano)
2. Describe the anal canal - parts, blood supply, nerve supply, lymphatics, and applied anatomy (hemorrhoids, fistula, carcinoma)
3. Describe the male perineum and external genitalia - deep perineal pouch contents and applied anatomy
4. Describe the female perineum - vulva, Bartholin glands, and applied anatomy

Lymphatics

1. Describe the lymphatic drainage of the abdomen - cisterna chyli, thoracic duct, and applied anatomy
2. Describe the lymphatic drainage of the gut

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SECTION B: SHORT NOTES - ABDOMEN & PELVIS

1. McBurney's point and its significance
2. Meckel's diverticulum - rule of 2s
3. Calot's triangle - boundaries and contents
4. Portal hypertension and portocaval anastomoses
5. Referred pain in the abdomen
6. Lobes of the liver and their surgical significance
7. Epiploic foramen (foramen of Winslow) - boundaries
8. Posterior relations of the stomach (stomach bed)
9. Superior mesenteric artery syndrome
10. Nutcracker phenomenon
11. Psoas abscess
12. Femoral hernia - boundaries of femoral canal, femoral triangle
13. Inguinal hernia - direct vs indirect differences
14. Hesselbach's triangle
15. Deep inguinal ring vs superficial inguinal ring
16. Coverings of spermatic cord and their embryological equivalents
17. Gubernaculum and its remnant in female
18. Processus vaginalis and its fate
19. Peritoneal pouches in the male and female pelvis
20. Pudendal nerve - course and applied anatomy (pudendal block)
21. Obturator nerve - course and applied anatomy
22. Lumbosacral trunk
23. Urogenital diaphragm (perineal membrane) - contents
24. Perineal body (central tendon of perineum)
25. Rectovesical pouch and rectouterine pouch (pouch of Douglas)
26. Clinical significance of pouch of Douglas
27. Supports of the uterus
28. Pelvic splanchnic nerves (nervi erigentes)
29. Hypogastric plexus
30. Presacral neurectomy
31. Arcuate line (linea semicircularis)
32. Spigelian hernia
33. Umbilical hernia and paraumbilical hernia
34. Nerve supply of the urinary bladder and micturition reflex
35. Fascial compartments of the penis
36. Lymphatics of the testis vs scrotum
37. Descent of the testis
38. Tributaries of the portal vein
39. Bare area of the liver
40. Ligamentum teres and ligamentum venosum
41. Subphrenic spaces
42. Duodenojejunal flexure (ligament of Treitz)
43. Blood supply of the rectum and anal canal
44. Extraperitoneal structures - retroperitoneal organs
45. Hilum of the kidney - structures in order
46. Left suprarenal gland vs right suprarenal gland
47. Phrenic nerve - course and applied anatomy
48. Crura of the diaphragm
49. Aortic hiatus vs esophageal hiatus vs caval opening
50. Applied anatomy of the femoral sheath

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SECTION C: APPLIED / REASONING SHORT NOTES - ABDOMEN & PELVIS

1. Why is indirect inguinal hernia more common in males? - Explain with processus vaginalis and descent of testis
2. Why is right-sided inguinal hernia more common? - Later descent of right testis
3. Why does femoral hernia occur more in females? - Wider pelvis, femoral canal dimensions
4. Why is portal hypertension followed by splenomegaly and ascites? - Portal venous anatomy
5. Why does carcinoma of head of pancreas cause painless obstructive jaundice? - CBD compression at head
6. Why is pain of appendicitis initially periumbilical? - Referred pain via T10 dermatome
7. Why does ureteric colic radiate to the groin, scrotum/labia? - Same nerve supply as genitofemoral nerve (L1, L2)
8. Why does adrenal left vein drain into renal vein while right drains directly into IVC? - Developmental asymmetry
9. Why is the left testicular vein longer and drains at a right angle into renal vein making varicocele more common on the left?
10. Why does carcinoma of body/tail of pancreas present late? - No early obstructive features
11. Why does hiatus hernia cause GERD? - Disruption of gastroesophageal junction
12. Why is splenic rupture dangerous? - Rich blood supply, capsule properties
13. Why does a posterior duodenal ulcer cause more serious bleeding? - Gastroduodenal artery erosion
14. Why does posterior gastric perforation lead to lesser sac collection?
15. Why does the rectum not have taenia coli, haustra, or appendices epiploicae? - Structural features of colon vs rectum
16. Why is the pelvic ureter at risk during hysterectomy? - Crossing of uterine artery
17. Why is the prostate gland drained by lymphatics to internal iliac nodes while testes drain to para-aortic nodes? - Developmental origin difference
18. Why does BPH obstruct urine flow? - Median lobe enlargement compresses urethra
19. Why is the posterior fornix of vagina the most dependent part for ectopic pregnancy rupture collection? - Pouch of Douglas
20. Why is Meckel's diverticulum clinically significant? - Rule of 2s, peptic ulceration from ectopic gastric mucosa

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SECTION D: EMBRYOLOGY - ABDOMEN & PELVIS

Long Answer Questions (Embryology)

1. Describe the development of the gut - foregut, midgut, hindgut with clinical correlations
2. Describe the development of the stomach and its rotations with clinical significance
3. Describe the development of the liver and biliary apparatus with anomalies
4. Describe the development of the pancreas (dorsal and ventral) with anomalies (annular pancreas, pancreas divisum)
5. Describe the development of the midgut - rotation, fixation, and anomalies (malrotation, volvulus, Meckel's diverticulum)
6. Describe the development of the urinary system - pronephros, mesonephros, metanephros, and anomalies
7. Describe the development of the kidney - ascent, rotation, and anomalies (horseshoe kidney, pelvic kidney, duplex ureter)
8. Describe the development of the gonads and genital ducts in both sexes with differentiation
9. Describe the descent of the testis and its anomalies (cryptorchidism, ectopic testis)
10. Describe the development of the uterus, vagina, and anomalies (bicornuate uterus, septate uterus, vaginal atresia)
11. Describe the development of the urorectal septum, cloacal membrane, and their divisions
12. Describe the development of the anterior abdominal wall and umbilicus with anomalies (gastroschisis, omphalocele, patent urachus)
13. Describe the development of the peritoneum and mesenteries
14. Describe the development of the suprarenal gland

Short Notes (Embryology)

1. Vitelline duct (omphalomesenteric duct) and its remnants
2. Physiological umbilical herniation - stages and timing
3. Annular pancreas - development and clinical features
4. Hirschsprung's disease (congenital aganglionic megacolon) - neural crest cell migration failure
5. Rotation of the midgut - degrees of rotation
6. Foregut, midgut, hindgut boundaries and derivatives
7. Development of the spleen - dorsal mesogastrium
8. Müllerian duct (paramesonephric duct) and its derivatives
9. Wolffian duct (mesonephric duct) and its derivatives
10. Gubernaculum - role in testicular and ovarian descent
11. Patent urachus and urachal cysts
12. Ectopia vesicae (bladder exstrophy) - development
13. Hypospadias vs epispadias - developmental basis
14. Development of external genitalia - indifferent stage and differentiation
15. Cloacal membrane and proctodeum
16. Atresia of the gut (duodenal atresia, jejunal atresia) - causes
17. Congenital pyloric stenosis - hypertrophy of pyloric sphincter
18. Persistence of processus vaginalis - types of hydrocele
19. Intersex states - true hermaphroditism, male pseudohermaphroditism
20. Development of the diaphragm - pleuroperitoneal membrane and anomalies (CDH - congenital diaphragmatic hernia)

What to Label (Embryology Diagrams - Abdomen & Pelvis)

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SECTION E: HISTOLOGY - ABDOMEN & PELVIS

Short Notes (Histology)

1. Histology of the esophagus - layers and special features (non-keratinized stratified squamous epithelium)
2. Histology of the stomach - layers, gastric glands, cell types (chief cells, parietal cells, mucous cells, G cells)
3. Histology of the duodenum - Brunner's glands, villi, crypts of Lieberkühn
4. Histology of the jejunum - tall villi, plicae circulares, goblet cells
5. Histology of the ileum - shorter villi, Peyer's patches, goblet cells more numerous
6. Histology of the large intestine - no villi, crypts prominent, abundant goblet cells, taenia coli
7. Histology of the appendix - lymphoid nodules, narrow lumen, no villi
8. Histology of the liver - hepatic lobule, portal triad, sinusoids, central vein, space of Disse, Kupffer cells
9. Histology of the gall bladder - simple columnar epithelium, Rokitansky-Aschoff sinuses, no muscularis mucosae, no submucosa
10. Histology of the pancreas - exocrine (acini, centroacinar cells, intercalated ducts) vs endocrine (islets of Langerhans: α, β, δ cells)
11. Histology of the kidney - cortex (glomerulus, Bowman's capsule, PCT, DCT), medulla (loop of Henle, collecting duct), juxtaglomerular apparatus
12. Histology of the suprarenal gland - cortex (zona glomerulosa, zona fasciculata, zona reticularis) vs medulla (chromaffin cells)
13. Histology of the ureter - transitional epithelium (urothelium), inner longitudinal and outer circular smooth muscle, adventitia
14. Histology of the urinary bladder - transitional epithelium, detrusor muscle (3 layers), umbrella cells
15. Histology of the testis - seminiferous tubules (Sertoli cells, spermatogonia, primary spermatocytes, secondary spermatocytes, spermatids, spermatozoa), interstitial cells of Leydig
16. Histology of the epididymis - pseudostratified columnar epithelium with stereocilia
17. Histology of the uterus - endometrium (functional and basal layers, simple columnar epithelium, uterine glands, stroma), myometrium, perimetrium
18. Histology of the ovary - germinal epithelium, tunica albuginea, cortex (follicles at various stages), medulla
19. Histology of the spleen - red pulp (sinusoids, splenic cords of Billroth), white pulp (PALS, Malpighian corpuscle, marginal zone)
20. Histology of the lymph node - capsule, cortex (primary follicles, secondary follicles with germinal center), paracortex, medulla (medullary cords, medullary sinuses), hilum

What to Label (Histology Diagrams - Abdomen & Pelvis)

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PART 2: LOWER LIMB

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SECTION A: LONG ANSWER QUESTIONS (LAQ) - LOWER LIMB

Bones and Joints

1. Describe the hip joint - type, articular surfaces, capsule, ligaments, blood supply, nerve supply, movements, relations, and applied anatomy (dislocation, fracture neck of femur)
2. Describe the knee joint - type, articular surfaces, capsule, ligaments (intracapsular and extracapsular), menisci, bursae, locking and unlocking mechanism, blood supply, nerve supply, and applied anatomy
3. Describe the ankle joint (talocrural joint) - type, articular surfaces, capsule, ligaments, movements, and applied anatomy (sprain, fractures)
4. Describe the subtalar joint and inversion/eversion of the foot with applied anatomy (flat foot, club foot)
5. Describe the arches of the foot - medial longitudinal arch, lateral longitudinal arch, transverse arch - supports, clinical significance (flat foot, pes cavus)

Muscles - Gluteal Region

1. Describe gluteus maximus - origin, insertion, nerve supply, actions, and applied anatomy (intramuscular injection site)
2. Describe the short external rotators of the hip and their applied anatomy (piriformis syndrome)
3. Describe gluteus medius and gluteus minimus - origin, insertion, nerve supply, actions, and applied anatomy (Trendelenburg sign and gait)

Muscles - Thigh

1. Describe the quadriceps femoris - components, origin, insertion, nerve supply, and applied anatomy
2. Describe the adductor group of muscles - components, nerve supply, and clinical significance (adductor canal, Hunter's canal)
3. Describe the hamstring muscles - components, origin, insertion, nerve supply, and applied anatomy (hamstring injury)
4. Describe the femoral triangle - boundaries, floor, roof, contents, and applied anatomy (femoral artery puncture, femoral hernia)
5. Describe the adductor (Hunter's) canal - boundaries, contents, and applied anatomy
6. Describe the popliteal fossa - boundaries, roof, floor, contents, and applied anatomy (popliteal aneurysm, Baker's cyst)

Muscles - Leg

1. Describe the muscles of the anterior compartment of the leg - components, nerve supply, actions, and applied anatomy (foot drop)
2. Describe the muscles of the posterior compartment of the leg - superficial and deep - nerve supply, actions, and applied anatomy
3. Describe the muscles of the lateral (peroneal) compartment - nerve supply, actions, and applied anatomy (eversion of foot)
4. Describe the extensor retinacula and flexor retinacula of the ankle with the structures passing beneath them

Nerves

1. Describe the femoral nerve - origin, course, branches, distribution, and applied anatomy (femoral nerve injury, femoral nerve block)
2. Describe the obturator nerve - origin, course, branches, distribution, and applied anatomy (obturator hernia, referred pain in hip disease)
3. Describe the sciatic nerve - origin, course, relations, branches, and applied anatomy (sciatic nerve injury, sciatica)
4. Describe the common peroneal (fibular) nerve - origin, course, branches, and applied anatomy (foot drop, nerve injury at neck of fibula)
5. Describe the tibial nerve - origin, course, branches, and applied anatomy (tarsal tunnel syndrome)
6. Describe the lumbosacral plexus - formation, branches, and applied anatomy
7. Describe the sacral plexus - formation, branches, and applied anatomy

Blood Vessels

1. Describe the femoral artery - origin, course, branches, and applied anatomy (femoral artery cannulation, femoral pulse)
2. Describe the popliteal artery - origin, course, branches, and applied anatomy (popliteal aneurysm, intermittent claudication)
3. Describe the arterial supply of the lower limb - anastomoses around the hip and knee
4. Describe the venous drainage of the lower limb - superficial (great and small saphenous veins) and deep veins, perforating veins, and applied anatomy (varicose veins, DVT)
5. Describe the lymphatic drainage of the lower limb - superficial and deep, inguinal lymph nodes, and applied anatomy

Fascia and Compartments

1. Describe the fascial compartments of the leg and their contents - applied anatomy (compartment syndrome)
2. Describe the fascia lata - iliotibial tract and its clinical significance

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SECTION B: SHORT NOTES - LOWER LIMB

1. Femoral sheath - formation, compartments, femoral canal, femoral ring
2. Femoral canal - boundaries, contents, clinical significance
3. Cruciate ligaments of the knee - anterior and posterior - functions and injury
4. Medial and lateral menisci - differences and clinical significance (meniscal tear)
5. Unhappy triad (O'Donoghue's triad) of the knee
6. Locking and unlocking of the knee joint
7. Bursae around the knee joint - clinically important ones
8. Screw home mechanism of the knee
9. Coxa vara and coxa valga - angle of inclination
10. Angle of anteversion of the femoral neck
11. Trendelenburg sign and Trendelenburg gait - mechanism
12. Nerve supply of the hip joint - Hilton's law applied
13. Blood supply of the head of femur - avascular necrosis
14. Q angle (quadriceps angle) and its significance
15. Iliotibial band friction syndrome
16. Patella - ossification, bipartite patella, patellar reflex
17. Great saphenous vein - course, tributaries, perforators, and clinical significance
18. Small saphenous vein - course and tributaries
19. Deep vein thrombosis (DVT) - Virchow's triad, Homans' sign
20. Varicose veins - mechanism, saphenofemoral junction
21. Popliteal pulse - clinical examination
22. Posterior tibial pulse - tarsal tunnel location
23. Dorsalis pedis artery - course and palpation
24. Lateral cutaneous nerve of the thigh - meralgia paresthetica
25. Saphenous nerve - course and applied anatomy
26. Sural nerve - formation and applied anatomy (nerve graft)
27. Superior gluteal nerve vs inferior gluteal nerve
28. Piriformis syndrome and sciatic nerve
29. Deep peroneal (fibular) nerve - first web space sensation
30. Superficial peroneal nerve - dorsum of foot sensation
31. Tarsal tunnel syndrome - tibial nerve compression
32. Intramuscular injection in gluteal region - safe quadrant
33. Morton's neuroma
34. Plantar fasciitis
35. Achilles tendon (tendo calcaneus) - clinical significance (Achilles tendinitis, rupture)
36. Peroneal (fibular) retinacula
37. Extensor hallucis longus and its applied anatomy (hallux valgus)
38. Sartorius muscle - "tailor's muscle" - all features
39. Tensor fascia lata - origin, insertion, actions
40. Pectineus - dual nerve supply
41. Obturator internus - nerve supply (nerve to obturator internus)
42. Nerve to quadratus femoris
43. Foot drop - causes, muscles affected, nerve involved
44. Claw toes vs hammer toe - differences
45. Pes planus (flat foot) - causes and supports of medial longitudinal arch
46. Club foot (talipes equinovarus) - deformities
47. Femoral nerve stretch test vs straight leg raise test
48. Compartment syndrome of the leg - Volkmann's ischemia equivalent
49. Ostiofascial compartments of the thigh
50. Knee aspiration - suprapatellar bursa

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SECTION C: APPLIED / REASONING SHORT NOTES - LOWER LIMB

1. Why does sciatic nerve injury at the gluteal region cause total loss of all movements below the knee? - All branches affected
2. Why does common peroneal nerve injury at the neck of fibula cause foot drop? - Deep peroneal nerve to dorsiflexors
3. Why does foot drop cause "steppage gait"? - To compensate for inability to dorsiflex
4. Why is the blood supply to the femoral head vulnerable in fracture neck of femur? - Retinacular vessels and their anatomy
5. Why is avascular necrosis common after intracapsular fracture of the neck of femur and not extracapsular? - Intracapsular position of retinacular vessels
6. Why does hip dislocation (posterior) injure the sciatic nerve? - Sciatic nerve proximity posterior to hip joint
7. Why does superior gluteal nerve injury cause Trendelenburg gait? - Gluteus medius/minimus paralysis
8. Why is the intramuscular injection given in the upper outer quadrant of the buttock? - To avoid sciatic and inferior gluteal nerves
9. Why is the great saphenous vein preferred for vascular bypass? - Longest superficial vein, easily accessible, consistent course
10. Why does DVT commonly occur in the lower limb? - Valve-rich system, slow flow, Virchow's triad
11. Why does long saphenous vein incompetence cause varicose veins? - Saphenofemoral junction incompetence, venous hypertension
12. Why is the popliteal artery the most important artery to check in supracondylar fracture of femur? - Artery tethered to bone
13. Why does obturator nerve irritation cause referred pain to the medial aspect of the knee? - Articular branch to the knee
14. Why does medial meniscus tear more often than lateral? - Attached to medial collateral ligament, less mobile
15. Why does the knee joint get locked in full extension? - Screw home mechanism, medial rotation of femur
16. Why is ankle sprain most common on the lateral side? - Lateral ligament weaker than medial (deltoid) ligament
17. Why does eversion injury cause more bone damage (Pott's fracture) than inversion? - Strong deltoid ligament avulses bone rather than tearing
18. Why does flat foot develop? - Failure of tibialis posterior (main dynamic support of medial arch)
19. Why is the saphenous nerve important after great saphenous vein harvest? - Travels with the vein, may be injured
20. Why does proximal fibula fracture (Maisonneuve fracture) injure the common peroneal nerve? - Nerve winds around the neck of fibula

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SECTION D: EMBRYOLOGY - LOWER LIMB

Short Notes (Embryology)

1. Development of the lower limb bud - timing, limb bud components (apical ectodermal ridge, zone of polarizing activity, progress zone)
2. Development of the bones of the lower limb from the condensed mesenchyme
3. Rotation of the lower limb bud - preaxial and postaxial borders - medial rotation in lower limb (contrast with lateral in upper limb)
4. Development of the femur - primary and secondary ossification centers
5. Development of the patella - ossification (only secondary center)
6. Development of the knee joint - intraarticular structures from mesenchyme
7. Congenital dislocation of the hip (CDH / developmental dysplasia of hip) - embryological basis
8. Club foot (talipes equinovarus) - developmental basis
9. Limb defects - amelia, phocomelia, hemimelia - causes
10. Polydactyly and syndactyly - developmental basis

What to Label (Embryology Diagrams - Lower Limb)

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SECTION E: HISTOLOGY - LOWER LIMB

Short Notes (Histology)

1. Histology of hyaline cartilage (articular cartilage of joints) - matrix, chondrocytes in lacunae, isogenous groups, no perichondrium on articular surface
2. Histology of fibrocartilage (menisci, intervertebral disc) - rows of chondrocytes between collagen bundles, no perichondrium
3. Histology of the synovial membrane - types A and B synoviocytes, vascular loose connective tissue, no basement membrane
4. Histology of dense regular connective tissue (tendons and ligaments) - parallel collagen bundles, tenocytes (fibrocytes) in rows
5. Histology of skeletal muscle - cross striations, peripheral nuclei, endomysium, perimysium, epimysium, A band, I band, H zone, Z line, M line
6. Histology of peripheral nerve (cross-section) - endoneurium, perineurium, epineurium, myelinated vs unmyelinated fibers, Schwann cells, nodes of Ranvier
7. Histology of a large artery (elastic artery) - tunica intima, tunica media (elastic lamellae), tunica adventitia
8. Histology of a medium artery (muscular artery) - internal elastic lamina, smooth muscle media, external elastic lamina
9. Histology of a vein (large vein) - thin walls, large lumen, valves, prominent tunica adventitia
10. Histology of lymph node - (same as above in abdominal section, applied to inguinal nodes)

What to Label (Histology Diagrams - Lower Limb)

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MASTER QUICK-REFERENCE SUMMARY TABLE

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TIPS FOR EXAM PREPARATION

• LAQs always follow the format: definition/intro → position/location → parts → relations → blood supply → nerve supply → lymphatics → applied anatomy
• Applied/Reasoning questions always explain the "why" - know the anatomical basis for each clinical fact
• Embryology - always mention the week of development, the germ layer of origin, and at least 2-3 anomalies per organ
• Histology labeling - practice identifying the section (LS/TS), the organ, and all labeled structures by their staining characteristics (H&E: eosinophilic vs basophilic, granules, etc.)
• For embryology diagrams - always label arrows showing direction of rotation/migration
• The "rule of 2s" for Meckel's, the "rule of 10s" for pheochromocytoma, and common portocaval anastomosis sites are high-yield clinical correlations

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COMPLETE ANSWERS: 1st YEAR MBBS ANATOMY

Abdomen & Pelvis + Lower Limb - All Questions Answered

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PART 1: ABDOMEN & PELVIS

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SECTION A: LONG ANSWER QUESTIONS (LAQ) - ABDOMEN & PELVIS

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Q1. Inguinal Canal - Formation, Walls, Contents, Applied Anatomy

• Length: 4 cm
• Direction: Downward, forward, and medially

• Deep (internal) inguinal ring: Oval opening in the transversalis fascia, located 1.25 cm above the midpoint of the inguinal ligament (midinguinal point), lateral to the inferior epigastric artery
• Superficial (external) inguinal ring: Triangular opening in the external oblique aponeurosis, above and medial to the pubic tubercle

• Spermatic cord (with its 3 layers, 3 arteries, 3 nerves, 2 veins, 1 lymphatic)
• Ilioinguinal nerve (traverses canal but not in spermatic cord)

• Round ligament of uterus
• Ilioinguinal nerve

1. Indirect inguinal hernia - enters deep ring lateral to inferior epigastric artery, traverses the full length of the canal, exits at superficial ring
2. Direct inguinal hernia - pushes directly through the posterior wall (Hesselbach's triangle), medial to inferior epigastric artery, does NOT enter deep ring
3. Hydrocele - patent processus vaginalis
4. Cremasteric reflex - tests L1 spinal cord level
5. The oblique direction of the canal is a protective mechanism - increased intra-abdominal pressure compresses the canal, closing it

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Q2. Rectus Sheath - Formation, Contents, Clinical Significance

• Midway between umbilicus and pubic symphysis
• Below this line, all aponeuroses pass anterior to rectus abdominis
• This creates a weak spot

1. Rectus abdominis muscle
2. Pyramidalis muscle (small, inconstant, lies in front of lower rectus)
3. Superior epigastric artery (from internal thoracic)
4. Inferior epigastric artery (from external iliac)
5. Superior and inferior epigastric veins
6. Terminal parts of lower 5 intercostal nerves and subcostal nerve
7. Lymphatics

1. Rectus sheath hematoma - injury to epigastric vessels (below arcuate line, hematoma spreads freely; above arcuate line, confined)
2. Midline incisions - through linea alba, bloodless
3. Paramedian incision - through rectus sheath
4. Spigelian hernia - at lateral border of rectus sheath at arcuate line

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Q3. Inguinal Ligament and Its Derivatives

• Length: ~12-14 cm
• Directed downward and medially
• Lower surface forms the floor of the inguinal canal

• Iliopsoas muscle
• Femoral nerve
• Lateral cutaneous nerve of the thigh

• Femoral artery (lateral)
• Femoral vein (medial)
• Femoral canal with lymphatics (most medial)

• Site of femoral and inguinal hernias
• Femoral artery cannulation landmark
• Lacunar ligament may strangulate femoral hernias

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Q4. Layers of the Anterior Abdominal Wall

1. Skin - thin and elastic
2. Superficial fascia (Camper's fascia) - fatty layer, continuous with general superficial fascia
3. Deep layer of superficial fascia (Scarpa's fascia) - membranous layer, continuous with dartos of scrotum (Colles' fascia in perineum)
4. External oblique muscle and aponeurosis - fibers run downward and medially ("hands in pockets")
5. Internal oblique muscle and aponeurosis - fibers run upward and medially (perpendicular to external oblique mostly)
6. Transversus abdominis muscle and aponeurosis - horizontal fibers; deepest flat muscle
7. Transversalis fascia - internal investing fascia of entire abdomen; forms deep inguinal ring
8. Extraperitoneal fat (preperitoneal fat)
9. Parietal peritoneum

• Lower 6 thoracic nerves (T7-T12) - intercostal and subcostal nerves
• Iliohypogastric nerve (L1) - supplies skin above pubis
• Ilioinguinal nerve (L1) - supplies skin of inguinal region, scrotum/labia

• Arterial: Superior epigastric (from internal thoracic), inferior epigastric (from external iliac), superficial epigastric (from femoral), deep circumflex iliac, superficial circumflex iliac, posterior intercostal arteries
• Venous: Corresponding veins; thoraco-epigastric veins connect superior and inferior epigastric systems

• Caput medusae (dilated periumbilical veins in portal hypertension) - via paraumbilical veins
• Planes of surgical incisions
• Site of hernias (umbilical, epigastric, inguinal, femoral, spigelian)

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Q5. Peritoneum - Subdivisions, Reflections, Recesses

• Parietal peritoneum: Lines the abdominal and pelvic walls; supplied by somatic nerves (pain well localized)
• Visceral peritoneum: Covers organs; supplied by autonomic nerves (pain poorly localized, referred)

• Greater sac: Main peritoneal cavity
• Lesser sac (omental bursa): Behind stomach and lesser omentum

• Subphrenic spaces (right and left)
• Subhepatic spaces (right and left)
• Hepatorenal pouch (Morrison's pouch) - most dependent in supine position
• Rectovesical pouch (male) - most dependent in erect male
• Rectouterine pouch (Douglas) - most dependent in female
• Paracolic gutters (right and left)
• Mesenteric recesses (superior/inferior duodenal, paracaecal, intersigmoid)

1. Peritoneal dialysis - use of peritoneal membrane as dialyzing membrane; dialysate instilled via catheter; works by osmosis/diffusion across parietal peritoneum
2. Peritonitis - inflammation causes board-like rigidity (somatic pain)
3. Ascites - fluid accumulates in peritoneal cavity; drained by paracentesis
4. Subphrenic abscess - after surgery/perforation
5. Ectopic implantation in peritoneal pregnancy

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Q6. Lesser Sac (Omental Bursa)

• Anterior: Free border of lesser omentum (portal vein, hepatic artery, bile duct - Pringle's maneuver)
• Posterior: Inferior vena cava
• Superior: Caudate lobe of liver
• Inferior: First part of duodenum

1. Pancreatic pseudocyst - collections in lesser sac after pancreatitis
2. Posterior gastric perforation - leaks into lesser sac (loculated)
3. Pringle's maneuver - finger in epiploic foramen to compress portal triad (controls liver bleeding)
4. Access - entered surgically through gastrocolic omentum to reach pancreas

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Q7. Greater Omentum

• Above: Greater curvature of stomach and first 2 cm of duodenum
• Below: Hangs down freely in front of small intestine
• Behind: Fuses with transverse mesocolon

• Right and left gastroepiploic (gastro-omental) arteries (from gastroduodenal and splenic arteries respectively)

1. "Policeman of the abdomen" - migrates to sites of infection/inflammation and walls them off (peritonitis, appendicitis)
2. Fat storage and insulation
3. Immune surveillance (milky spots = lymphoid aggregates)
4. Limits spread of infection

1. Omental patch repair - used to seal perforations (Graham patch for duodenal ulcer)
2. Omentoplasty - used to fill dead spaces, revascularize areas
3. Omental torsion - rare cause of acute abdomen
4. Carcinomatosis - peritoneal metastases often involve greater omentum (omental cake)

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Q8. Mesenteries of the Gut

• Superior mesenteric artery and its branches
• Tributaries of superior mesenteric vein
• Lymphatics and mesenteric lymph nodes (200+)
• Autonomic nerve plexuses
• Fat

1. Mesenteric cysts - arise in mesentery, can cause obstruction
2. Mesenteric ischemia - occlusion of SMA - "abdominal angina"
3. Volvulus - rotation of bowel on its mesentery
4. Mesenteric adenitis - lymph node enlargement mimicking appendicitis
5. Short bowel syndrome - after mesenteric resection

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Q9. Stomach - Complete Description

• Diaphragm (upper part - covered by left costal margin)
• Anterior abdominal wall (lower part - in epigastric region)
• Left lobe of liver (right side)

• Transverse mesocolon
• Splenic artery
• Left kidney (upper part)
• Left suprarenal
• Tail of pancreas
• Spleen

• Parasympathetic: Anterior and posterior vagal trunks (from left and right vagus)
• Sympathetic: T6-T9 via celiac plexus
• Pain: T6-T9 (referred to epigastrium)

• Lesser curvature → left gastric nodes → celiac nodes
• Greater curvature → right gastroepiploic nodes → pyloric nodes
• Fundus/upper left → left gastroepiploic/splenic nodes
• Pyloric region → subpyloric nodes

1. Peptic ulcer - common on lesser curvature
2. Gastrectomy (Billroth I, II) - needs knowledge of blood supply
3. Gastric cancer - lymphatic spread
4. Pyloroplasty, pyloromyotomy
5. Vagotomy - for reducing acid secretion

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Q10. Blood Supply of the Stomach

• Left gastric artery is the largest artery to the stomach and the first branch of the celiac trunk
• Right gastric artery is smallest of the gastric arteries
• Anastomoses: Left and right gastric arteries anastomose along lesser curvature; left and right gastroepiploic anastomose along greater curvature - this creates a rich anastomotic network

• Gastric ulcer bleeding: Most dangerous if on posterior wall of first part of duodenum (erodes gastroduodenal artery)
• Total gastrectomy requires ligation of all 5 sets of arteries
• Highly selective vagotomy preserves "crow's foot" of nerve of Latarjet to antrum and pylorus

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Q11. Duodenum - Parts, Relations, Blood Supply, Applied Anatomy

• Only mobile part (has peritoneum)
• Relations: Gallbladder (anterior/superior), portal vein/bile duct/gastroduodenal artery (posterior), epiploic foramen (posterior)
• Duodenal cap - site of duodenal ulcer

• Fixed retroperitoneal
• Bile duct and pancreatic duct open at major duodenal papilla (of Vater) on posteromedial wall
• Minor papilla (accessory pancreatic duct) 2 cm above
• Closely related to head of pancreas medially

• Crosses midline over aorta and IVC
• Superior mesenteric vessels cross anterior to it (SMA syndrome - compression)
• Root of mesentery crosses it

• Ascends to duodenojejunal flexure (DJF)
• DJF held by ligament of Treitz (suspensory muscle of duodenum)
• DJF at left of L2 vertebra

• Upper half (1st and upper 2nd part): Superior pancreaticoduodenal artery (from gastroduodenal artery - celiac territory)
• Lower half (lower 2nd, 3rd, 4th): Inferior pancreaticoduodenal artery (from SMA territory)
• These form anterior and posterior pancreaticoduodenal arcades

1. Duodenal ulcer - 1st part (posterior wall bleeds from gastroduodenal artery; anterior wall perforates into lesser sac)
2. SMA syndrome - 3rd part compressed between SMA and aorta (in thin patients, rapid weight loss)
3. Carcinoma of head of pancreas - 2nd part compressed
4. Duodenal atresia - "double bubble" sign on X-ray

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Q12. Jejunum and Ileum - Differences and Applied Anatomy

• Remnant of vitello-intestinal (omphalomesenteric) duct
• Rule of 2s: 2% population, 2 feet (60 cm) from ileocaecal junction, 2 inches long, 2 types of ectopic mucosa (gastric most common, also pancreatic), 2:1 male preponderance, presents in first 2 years
• Complications: Peptic ulceration (from ectopic gastric mucosa → bleeding/perforation), intestinal obstruction, diverticulitis (mimics appendicitis), intussusception, Littre's hernia (Meckel's in hernia sac)
• Technetium-99m pertechnetate scan detects ectopic gastric mucosa

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Q13. Colon - Parts, Features, Blood Supply, Applied Anatomy

1. Taenia coli - 3 longitudinal bands of outer muscle (omentalis, libera, mesocolica); converge at base of appendix
2. Haustra (sacculations) - puckerings between taenia
3. Appendices epiploicae - fat-filled peritoneal tags
4. Wider caliber and thinner wall than small intestine

• Ileocolic artery → caecum, appendix, lower ascending colon
• Right colic artery → ascending colon
• Middle colic artery → transverse colon

• Left colic artery → descending colon, splenic flexure
• Sigmoid arteries → sigmoid colon
• Superior rectal artery → upper rectum

1. Carcinoma of colon - right colon (usually cecal/ascending - presents with iron deficiency anemia); left colon (obstructive symptoms, "apple core" on barium enema)
2. Diverticular disease - sigmoid colon most common
3. Colostomy and ileostomy - surgical anatomy
4. Splenic flexure carcinoma - watershed area between SMA and IMA

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Q14. Appendix - Position, Blood Supply, McBurney's Point, Referred Pain

1. Retrocaecal (65%) - most common; behind caecum
2. Pelvic (30%) - hangs into pelvis
3. Subcaecal
4. Pre-ileal
5. Post-ileal
6. Retroileal

• Appendicular artery - branch of ileocolic artery (from SMA)
• It is a "end artery" (no collaterals) - thrombosis → gangrene of appendix
• Runs in free border of mesoappendix

• Junction of medial 2/3 and lateral 1/3 of line joining umbilicus to right ASIS
• Surface marking of base of appendix
• Point of maximum tenderness in appendicitis
• Rovsing's sign - pressure on left iliac fossa causes pain in right iliac fossa
• Psoas sign - pain on passive extension of right hip (retrocaecal appendix)
• Obturator sign - pain on internal rotation of right hip (pelvic appendix)

• Early (visceral): Pain referred to periumbilical region (T10 dermatome) - via T10 autonomic afferents
• Late (somatic): Pain shifts to right iliac fossa at McBurney's point - parietal peritoneum irritated, well-localized

1. Gridiron incision or Lanz incision for appendicectomy
2. Retrocaecal appendix - delayed presentation, psoas sign
3. Pelvic appendix - pelvic peritonitis, frequency/dysuria
4. Appendicular lump/abscess
5. Carcinoid tumor - most common tumor of appendix

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Q15. Liver - Complete Description

• Diaphragmatic: Convex; right, anterior, superior, posterior parts
• Visceral: Concave; faces down and left; shows H-shaped impression

• Right lobe - largest
• Left lobe
• Quadrate lobe - between fossa for gallbladder and ligamentum teres (functionally left lobe)
• Caudate lobe - between fossa for IVC and ligamentum venosum (functionally either or has own portal supply)

• Falciform ligament (contains ligamentum teres = obliterated left umbilical vein)
• Coronary ligament (front and back leaves, with bare area between)
• Right and left triangular ligaments
• Lesser omentum (hepatogastric + hepatoduodenal ligaments)
• Ligamentum venosum (obliterated ductus venosus) in fissure

• Right lobe: Right kidney, right adrenal, hepatic flexure, gallbladder
• Left lobe: Stomach, lesser omentum

• Portal vein (75%): Nutrient blood from gut
• Hepatic artery proper (25%): Oxygenated blood (from celiac trunk → common hepatic → hepatic artery proper)

• 3 hepatic veins (right, middle, left) → IVC just before it enters the right atrium
• Note: Hepatic veins have no valves

• Sympathetic: T7-T10 (via celiac plexus)
• Parasympathetic: Vagus nerve
• Phrenic nerve (C3,4,5) - peritoneal covering; referred pain to shoulder tip

1. Hepatomegaly - downward and medial enlargement
2. Portal hypertension - blocked portal blood flow
3. Liver biopsy - right midaxillary line, 8th or 9th intercostal space
4. Liver abscess (amoebic) - right lobe most common
5. Hepatocellular carcinoma - associated with cirrhosis, hepatitis B/C
6. Couinaud segmentectomy - surgical resection

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Q16. Porta Hepatis

• Hepatic lymphatics (efferent to porta hepatis nodes)
• Hepatic nerve plexus
• Right and left hepatic ducts (emerging)

• Pringle's maneuver: Compression of free border of lesser omentum (portal triad) with finger and thumb to control bleeding during liver surgery
• Portal hypertension - block at any level (pre-hepatic, hepatic, post-hepatic)
• Hilar cholangiocarcinoma (Klatskin tumor) - affects confluence of hepatic ducts

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Q17. Portal Vein - Formation, Tributaries, Portocaval Anastomoses

• Superior mesenteric vein (SMV)
• Splenic vein (at the level of L2, behind neck of pancreas)

1. Superior mesenteric vein
2. Splenic vein (receives inferior mesenteric vein, short gastric veins, left gastroepiploic)
3. Left gastric (coronary) vein - directly to portal vein
4. Right gastric vein - directly
5. Cystic vein - from gallbladder
6. Paraumbilical veins - from umbilicus along ligamentum teres

1. Portal hypertension - cirrhosis most common cause; causes esophageal varices (most dangerous)
2. Esophageal varices - treated by banding, sclerotherapy, TIPS (transjugular intrahepatic portosystemic shunt)
3. Splenomegaly - due to back pressure
4. Ascites - increased portal pressure + hypoalbuminemia
5. Portal vein thrombosis - acute abdomen, intestinal ischemia

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Q18. Gall Bladder - Relations, Blood Supply, Applied Anatomy

• Superior: Liver (fossa)
• Inferior: Transverse colon, hepatic flexure
• Posterior: First part of duodenum
• Fundus: Anterior abdominal wall

• Cystic artery (usually from right hepatic artery, but highly variable)
• Cystic vein → right branch of portal vein (or directly to liver)

• Cystic artery (surgical landmark - must identify before dividing)
• Right hepatic artery (courses through it)
• Cystic lymph node (Lund's node / sentinel node)

1. Cholecystitis - inflammation; Murphy's sign (inspiratory arrest on deep palpation of right hypochondrium)
2. Gallstones (cholelithiasis) - most common site of obstruction: Hartmann's pouch (neck), cystic duct, CBD
3. Laparoscopic cholecystectomy - safe identification of Calot's triangle prevents bile duct injury
4. Mirizzi syndrome - gallstone impacted in cystic duct compressing CHD
5. Courvoisier's law - painless distended gallbladder + jaundice = carcinoma of head of pancreas (not gallstones, because gallstones cause fibrosis making gallbladder non-distensible)
6. Hartmann's pouch - recess at neck; gallstones lodge here

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Q19. Extrahepatic Biliary Apparatus

1. Right and left hepatic ducts - emerge from right and left lobes at porta hepatis
2. Common hepatic duct (CHD) - formed by union of right and left hepatic ducts; 3 cm long
3. Cystic duct - from gallbladder; joins CHD
4. Common bile duct (CBD) - from CHD + cystic duct junction; ~8 cm; passes behind first part of duodenum, then in groove on posterior surface of head of pancreas, opens at major duodenal papilla (of Vater) with main pancreatic duct

1. Supraduodenal part - in free border of lesser omentum
2. Retroduodenal part - behind first part of duodenum
3. Infraduodenal (pancreatic) part - in groove of pancreatic head
4. Intraduodenal part - passes obliquely through wall of 2nd part of duodenum

1. Obstructive jaundice - CBD blocked by stone, stricture, or carcinoma (of head of pancreas)
2. ERCP - endoscopic retrograde cholangiopancreatography - access via papilla
3. Choledocholithiasis - stone in CBD
4. T-tube choledochotomy - surgical drainage of CBD
5. Anatomical variation of cystic duct-CHD junction (important in cholecystectomy)

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Q20. Pancreas

• Main duct (Wirsung) - runs through full length; joins CBD at ampulla of Vater
• Accessory duct (Santorini) - drains upper head; opens at minor papilla, 2 cm above major

• Head: Superior and inferior pancreaticoduodenal arteries (from gastroduodenal and SMA)
• Body and tail: Splenic artery branches (dorsal pancreatic, great pancreatic, caudal pancreatic arteries)

1. Acute pancreatitis - amylase/lipase elevated; severe epigastric pain radiating to back; "cullen's sign" (periumbilical bruising), "Grey Turner sign" (flank bruising)
2. Carcinoma of head of pancreas - painless obstructive jaundice; Courvoisier's sign; compression of CBD; poor prognosis
3. Annular pancreas - developmental anomaly; encircles duodenum → obstruction
4. Pancreas divisum - dorsal and ventral parts fail to fuse
5. Pancreatic pseudocyst - post-pancreatitis fluid in lesser sac
6. Whipple's procedure (pancreaticoduodenectomy) - for cancer of head

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Q21. Spleen

• Diaphragmatic: Convex; faces upward, backward, and laterally
• Visceral: Concave; faces downward and medially; has gastric, renal, and colic impressions; hilum on medial border

• Posterior: Diaphragm, 9th-11th ribs
• Anterior: Stomach (gastrosplenic ligament)
• Medial: Left kidney and adrenal (splenorenal ligament), tail of pancreas
• Inferior: Splenic flexure of colon

• Splenic artery (largest branch of celiac trunk) - tortuous course along upper border of pancreas; branches at hilum
• Splenic vein - joins SMV to form portal vein

• Gastrosplenic ligament - contains short gastric and left gastroepiploic arteries
• Splenorenal ligament - contains splenic vessels, tail of pancreas

1. Splenomegaly - enlarges downward and medially toward right iliac fossa; never reaches midline; has notched anterior border (distinguishes from kidney enlargement)
2. Splenic rupture - common in blunt abdominal trauma; can be delayed (subcapsular hematoma); Kehr's sign (referred pain to left shoulder tip via phrenic nerve)
3. Splenectomy - increased risk of post-splenectomy sepsis (OPSI) - encapsulated organisms (Streptococcus pneumoniae, Haemophilus, Meningococcus); vaccination required
4. Accessory spleen - in 10-30% people; must be removed in hemolytic conditions

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Q22. Kidneys - Position, Relations, Blood Supply, Applied Anatomy

• Diaphragm (upper 1/3 - ribs 11, 12 related)
• Psoas muscle (medial)
• Quadratus lumborum (lateral)
• Transversus abdominis muscle
• Subcostal nerve (T12), iliohypogastric and ilioinguinal nerves (L1)

• Renal arteries - direct branches of aorta at L1-2; right renal artery longer (crosses behind IVC, right renal vein, head of pancreas, and descending part of duodenum)
• 5 segmental arteries (all end arteries) → no collateral between segments → infarction if blocked
• Renal veins → IVC (left renal vein is longer, crosses in front of aorta and behind SMA)

1. Renal calculi - commonest at: pelviureteric junction, crossing iliac vessels, vesicoureteric junction
2. Percutaneous nephrolithotomy - through posterior relations (12th rib, posterior calyx)
3. Renal biopsy - posterior approach, lower pole
4. Nephrectomy - loin incision; danger of injuring nearby structures
5. Renal transplant - placed in iliac fossa (heterotopic); uses external iliac vessels
6. Horseshoe kidney - fused at lower poles; at risk during aortic aneurysm surgery

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Q23. Renal Fascia (Gerota's Fascia) and Perinephric Fat

• Anterior renal fascia (Gerota's) - in front of kidney
• Posterior renal fascia (Zuckerkandl's) - behind kidney

• Perirenal (perinephric) space - between layers of renal fascia; contains kidney, adrenal, perinephric fat
• Pararenal space - outside renal fascia

• Fused superiorly over diaphragm
• Open inferiorly (medially) - hence perinephric collections can drain down to pelvic brim
• Lateral sides fuse with transversalis fascia
• Medially continuous with connective tissue of great vessels

1. Perinephric abscess - collection in perirenal space; diagnosis by CT; drains inferiorly along psoas → groin
2. Retroperitoneal hematoma - trauma; contained by fascia
3. Perinephric fat - acts as shock absorber; reduced in cachexia → kidney more mobile ("floating kidney")
4. Renal fascia planes - used during retroperitoneal surgery
5. Wilms' tumor (nephroblastoma) - initially contained within renal fascia

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Q24. Ureter - Course, Relations, Constrictions, Blood Supply, Applied Anatomy

1. Begins at renal pelvis at the hilum (L1-2)
2. Descends on psoas muscle (retroperitoneal)
3. Crosses bifurcation of common iliac artery at pelvic brim (anterior - useful X-ray landmark)
4. Enters pelvis - runs on lateral pelvic wall to ischial spine
5. Turns medially and forward to reach bladder

• Right ureter: Duodenum, right colic vessels, ileocolic vessels, mesentery, right gonadal vessels (ureter behind)
• Left ureter: Sigmoid colon, left colic vessels, left gonadal vessels

• Gonadal vessels cross anterior to ureter
• In female: Uterine artery crosses over ureter 2 cm lateral to cervix ("water under the bridge")

1. Pelviureteric junction (PUJ) - where renal pelvis narrows to ureter
2. Pelvic brim - where ureter crosses common iliac bifurcation
3. Vesicoureteric junction (VUJ) - narrowest point; where ureter enters bladder obliquely

• Renal artery → upper ureter
• Gonadal artery → middle ureter
• Vesical arteries → lower ureter
• (Also: common iliac, internal iliac, middle rectal arteries)
• Runs on medial side in retroperitoneum (adventitia supplies blood)

1. Ureteric calculus - pain (renal colic) radiates from loin to groin, scrotum/labia majora (via genitofemoral nerve L1,L2)
2. Ureter injury in surgery - gynecological (hysterectomy - crossing of uterine artery), abdominal aortic surgery, colectomy
3. Ureteroscopy - retrograde approach via cystoscope
4. Hydronephrosis - back pressure dilatation due to obstruction
5. Megaloureter, ureteric duplication (common anomaly)

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Q25. Suprarenal (Adrenal) Glands

• Superior suprarenal artery - from inferior phrenic artery
• Middle suprarenal artery - directly from aorta
• Inferior suprarenal artery - from renal artery

• Right suprarenal vein → directly into IVC (short vein - surgical hazard)
• Left suprarenal vein → left renal vein (then to IVC)

1. Addison's disease - primary adrenal insufficiency; hyperpigmentation, hypotension, hyperkalemia
2. Cushing's syndrome - excess cortisol; central obesity, buffalo hump, striae
3. Pheochromocytoma - tumor of medullary chromaffin cells; "Rule of 10%"; paroxysmal hypertension
4. Primary aldosteronism (Conn's syndrome) - excess aldosterone; hypertension + hypokalemia
5. Adrenalectomy - right suprarenal vein is short → careful ligation needed to avoid IVC injury

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Q26. Abdominal Aorta

• Anterior: Lesser sac, stomach, pancreas, left renal vein, 3rd part of duodenum, mesentery root, small intestine
• Posterior: Vertebral bodies (L1-L4), anterior longitudinal ligament, left lumbar veins
• Right: IVC, right crus of diaphragm, cisterna chyli
• Left: Left sympathetic trunk

1. Celiac trunk - T12 level; supplies foregut (stomach to upper duodenum, liver, spleen, pancreas)
2. Superior mesenteric artery (SMA) - L1; supplies midgut (lower duodenum to 2/3 of transverse colon)
3. Inferior mesenteric artery (IMA) - L3; supplies hindgut (descending colon to upper rectum)

• Suprarenal (middle) arteries - at L1
• Renal arteries - at L1-2
• Gonadal (testicular/ovarian) arteries - at L2

• Inferior phrenic arteries
• 4 pairs of lumbar arteries
• Median sacral artery (terminal, unpaired)

1. Aortic aneurysm - fusiform dilation below renal arteries (most common site); rupture = surgical emergency; risk of injury to left renal vein, ureters
2. Leriche syndrome - aortoiliac occlusion; buttock claudication, impotence, absent femoral pulses
3. Celiac/SMA compression syndromes
4. Midline incision provides access to aorta

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Q27. Inferior Vena Cava (IVC)

• Anterior: 3rd part of duodenum, head of pancreas, right gonadal artery, mesentery, right common iliac artery, posterior surface of liver
• Posterior: Vertebral bodies, right psoas, right crus, right renal artery, right suprarenal artery, right inferior phrenic artery
• Right: Right ureter, right kidney
• Left: Aorta (below L4), caudate lobe of liver

1. Iliac veins (common)
2. Lumbar veins (4 pairs)
3. Testicular/Ovarian veins (right only drains directly; left drains to left renal vein)
4. Renal veins
5. Suprarenal veins (right only directly)
6. Hepatic veins (3)
7. Inferior phrenic veins

1. IVC thrombosis - bilateral leg edema
2. Filter placement - for recurrent PE; placed in IVC below renal veins
3. IVC injury during surgery - extremely dangerous hemorrhage
4. Left renal vein crosses anterior to aorta under SMA - compressed = nutcracker phenomenon

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Q28. Diaphragm

• Sternal part: 2 slips from posterior aspect of xiphoid
• Costal part: Inner surfaces of lower 6 costal cartilages
• Vertebral part: Right and left crura (from L1-3 and L1-2 respectively) + arcuate ligaments (medial and lateral)
• Medial arcuate ligament: Thickening of psoas fascia (L1 vertebra to transverse process of L1) - over psoas
• Lateral arcuate ligament: Thickening of quadratus lumborum fascia - over quadratus lumborum

• Left phrenic nerve: Pierces left dome of diaphragm
• Right phrenic nerve: Through caval opening or through right dome
• Hemiazygos vein: Through left crus
• Sympathetic trunks: Behind medial arcuate ligaments
• Splanchnic nerves: Pierce crura

• Motor and sensory to central tendon: Phrenic nerve (C3, 4, 5 - "C3, 4, 5 keeps the diaphragm alive")
• Sensory to peripheral part: Lower 5 intercostal nerves + subcostal nerve

• Musculophrenic arteries, pericardiophrenic arteries, superior and inferior phrenic arteries

1. Hiatus hernia - sliding (most common - cardiac end of stomach slides through esophageal hiatus) or rolling/paraesophageal (fundus herniates alongside esophagus)
2. GERD - incompetent lower esophageal sphincter + hiatus hernia
3. Congenital diaphragmatic hernia (CDH) - Bochdalek (posterolateral, left side > right); Morgagni (anterior, retrosternal)
4. Subphrenic abscess - between diaphragm and liver
5. Referred pain - phrenic nerve C3,4 = shoulder tip (C4 dermatome) - diaphragmatic irritation → shoulder tip pain
6. Hiccough (singultus) - irritation of phrenic or vagus nerve

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Q29. Lumbar Plexus

1. Psoas hematoma - compresses femoral nerve → weakness of knee extension + loss of patellar reflex
2. Lumbar plexus block - "3-in-1 block"
3. Meralgia paresthetica - entrapment of lateral cutaneous nerve of thigh at ASIS → burning pain/numbness lateral thigh
4. Obturator nerve - injured in obturator hernia

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Q30. Celiac Plexus

• Greater splanchnic nerves (T5-T9) - from thoracic sympathetic ganglia
• Lesser splanchnic nerves (T10-T11)
• Least splanchnic nerve (T12)
• Posterior vagal trunk (parasympathetic component)
• Celiac ganglia (paired, largest autonomic ganglia in body)

• Stomach, duodenum, small intestine, colon to splenic flexure
• Liver, gallbladder, pancreas, spleen
• Kidneys, adrenals

• Hepatic, gastric, splenic, mesenteric, renal, suprarenal, aortic plexuses

1. Celiac plexus block - for intractable pain in pancreatic cancer, upper GI malignancies; destroys celiac ganglia with alcohol/phenol; done under CT/fluoroscopic guidance
2. Referred pain - visceral pain from these organs referred to epigastric region
3. Solar plexus injury - blow to epigastrium; visceral response (nausea, bradycardia, fall in BP)

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Q31. Male Urethra

• Upper curve - concave downward (subpubic) - fixed
• Lower curve - concave upward (prepubic) - straightened when penis erected or catheter passed

1. Catheterization - pass along natural curves; size 14-16 Fr for adults; angle penis upward initially to straighten prepubic curve
2. Urethral rupture:
   • Membranous urethra - in pelvic fracture; above perineal membrane; urine extravasates into retropubic space
   • Bulbous urethra - straddle injury; below perineal membrane; urine in superficial perineal pouch → follows Colles' fascia
3. Urethral stricture - after infection (gonorrhea) or trauma; causes obstructive symptoms
4. BPH - prostatic urethra compressed

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Q32. Prostate Gland

• Transitional zone - periurethral; BPH origin (25%)
• Central zone - surrounds ejaculatory ducts (25%)
• Peripheral zone - posterior/posterolateral; carcinoma origin (70%)
• Anterior fibromuscular stroma

• Superior: Bladder neck, base of bladder
• Inferior: Urogenital diaphragm (external sphincter)
• Anterior: Pubic symphysis (retropubic space/cave of Retzius)
• Posterior: Rectum (anterior rectal wall; prostate palpable on DRE)
• Lateral: Levator ani

• Inferior vesical artery (from internal iliac) → main supply
• Middle rectal artery also contributes
• Prostatic venous plexus (Santorini's plexus) → iliac veins/vertebral veins

• Sympathetic (T10-L2): Contraction of smooth muscle (ejaculation)
• Parasympathetic (S2-4): Secretion

1. BPH (benign prostatic hyperplasia) - transitional zone/median lobe enlarges; compresses urethra; obstructive uropathy; treated by TURP
2. Carcinoma of prostate - peripheral zone; raised PSA; Gleason score; prone to bony metastases (lumbar vertebrae - via Batson's plexus/vertebral venous plexus)
3. Prostatitis - can mimic UTI symptoms
4. Digital rectal examination (DRE) - prostate palpable through anterior rectal wall (2 lateral lobes with median groove)
5. Radical prostatectomy - risk of impotence (neurovascular bundles of Walsh) and incontinence

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Q33. Urinary Bladder

• Superior: Pelvic colon, coils of small intestine
• Posterior (male): Seminal vesicles, vas deferens, ureters, rectovesical pouch, rectum
• Posterior (female): Uterus, vagina (vesicouterine pouch anteriorly)
• Inferior: Prostate (male), pelvic floor (female)

• Superior vesical artery (from internal iliac - patent part of umbilical artery)
• Inferior vesical artery (male); vaginal artery (female)
• Middle rectal artery

• Sympathetic (T11-L2): Relaxes detrusor, contracts internal sphincter (storage)
• Parasympathetic (S2-4): Contracts detrusor, relaxes internal sphincter (voiding)
• Somatic (pudendal S2-4): External sphincter

1. Suprapubic catheterization - possible when bladder full (rises above pubic symphysis) without opening peritoneum
2. Cystoscopy - trigone and ureteric orifices viewed
3. Vesicoureteric reflux - incompetent oblique insertion of ureter at VUJ
4. Bladder carcinoma - transitional cell; TURBT; cystectomy with urinary diversion
5. Neurogenic bladder - upper motor neuron (spastic) vs lower motor neuron (flaccid)

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Q34. Uterus

• Anterior: Vesicouterine pouch, bladder
• Posterior: Rectouterine pouch (Douglas), sigmoid colon, rectum
• Lateral: Broad ligament, uterine vessels, ureter (2 cm lateral to cervix)
• Superior: Coils of bowel

• Uterine artery (from internal iliac) - crosses ureter 2 cm lateral to cervix ("bridge over water")
• Ovarian artery (from aorta) - supplies fundus via ovarian ligament

• Sympathetic: L1,2 (uterine pain above internal os)
• Parasympathetic: S2-4 (erection in male; vasodilation in female)
• Pain from cervix/lower uterus: Pelvic splanchnic nerves S2-4

• Fundus → para-aortic nodes (with ovary)
• Body → internal/external iliac nodes
• Cervix → internal/external iliac, obturator nodes

• Primary supports: Cardinal (Mackenrodt's) ligaments, uterosacral ligaments
• Secondary: Round ligament (little support), broad ligament (little support)
• Pelvic floor (levator ani - most important indirect support)

1. Prolapse - weakened supports; stages I-III; common postmenopause
2. Fibroids (leiomyoma) - commonest pelvic tumor; submucosal, intramural, subserosal
3. Ectopic pregnancy - usually in fallopian tube (ampulla most common)
4. Hysterectomy - uterine artery ligation; risk of ureter injury at crossing
5. Retroversion - uterus tilted posteriorly; may cause backache
6. Vesicouterine fistula - post CS complication

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Q35. Broad Ligament

• Mesometrium - largest part; below uterine tube; main body of broad ligament
• Mesosalpinx - fold of peritoneum around uterine tube; between tube and ovary
• Mesovarium - posterior leaf of broad ligament attached to ovary

1. Uterus (in its fold)
2. Uterine tubes (in upper free border)
3. Round ligament (anteroinferior)
4. Ligament of ovary (posterior layer)
5. Uterine vessels and veins
6. Uterovaginal nerve plexus
7. Lymphatics
8. Ureter (at the base in the parametrium)
9. Vestigial remnants: epoophoron (Wolffian duct remnant), paroophoron
10. Gartner's duct cyst (in base)

1. Parametritis - infection of parametrium (cellular tissue in base of broad ligament)
2. Broad ligament hematoma - after uterine perforation
3. Broad ligament myoma - fibroid developing in parametrium
4. Broad ligament cysts - from remnants of Wolffian duct (Gartner's duct cysts)

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Q36. Round Ligament

• Attached to anterolateral aspect of uterus, below and anterior to uterine tube
• Passes laterally between folds of broad ligament
• Enters deep inguinal ring
• Traverses inguinal canal
• Exits through superficial inguinal ring
• Fans out into labium majus and mons pubis

• Round ligament
• Artery of round ligament (branch of inferior epigastric)
• Ilioinguinal nerve

1. Endometriosis - ectopic endometrial tissue can involve round ligament
2. Labial fibroma - fibroid of round ligament
3. Referred pain - uterine pain sometimes referred to labium via ilioinguinal nerve
4. Gubernaculum homology - in male descends with testis; in female forms ovarian and round ligaments; ovary does not descend completely because it is attached to Müllerian duct

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Q37. Ovary

• Mesovarium - to posterior layer of broad ligament
• Suspensory ligament (infundibulopelvic ligament) - to pelvic wall; contains ovarian vessels, nerves, lymphatics
• Ligament of ovary (ovarian ligament) - to uterus
• Tubo-ovarian ligament (loose) - to fimbriae of tube

• Medial: Uterine tube (fimbriae applied to ovary)
• Lateral: Pelvic wall (obturator vessels)
• Anterior: Broad ligament
• Posterior: Ureter and internal iliac vessels

• Ovarian artery - direct branch of abdominal aorta at L2
• Anastomoses with ovarian branch of uterine artery

• Right ovarian vein → IVC
• Left ovarian vein → left renal vein

1. Ovarian cyst - commonest adnexal mass; can cause torsion (acute abdomen), rupture
2. Ovarian torsion - twists on its pedicle; ischemia; acute pain; emergency surgery
3. Carcinoma ovary - most lethal gynecological cancer; spreads to peritoneum (carcinomatosis)
4. Endometrioma (chocolate cyst) - endometriosis
5. Left ovarian vein drains to left renal vein - varicocele in males (analogous left testicular vein)

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Q38. Fallopian Tube (Uterine Tube)

1. Intramural (interstitial) - 1 cm; narrowest; within uterine wall
2. Isthmus - 3 cm; narrow; next to uterus
3. Ampulla - 5 cm; widest, tortuous; site of fertilization
4. Infundibulum - 2 cm; funnel-shaped; fimbriated end (fimbriae); one fimbria - ovarian fimbria - attached to ovary

• Medial 2/3: Tubal branch of uterine artery
• Lateral 1/3: Tubal branch of ovarian artery

1. Ectopic pregnancy - fertilized ovum implants in tube (most common site: ampulla); causes acute abdomen when it ruptures; tearing of tubal arteries → intraperitoneal hemorrhage; blood collects in pouch of Douglas
2. Salpingitis - tubal infection (often PID); can lead to tubal occlusion and infertility
3. Tubal ligation - common sterilization method; isthmus ligated/clipped
4. Salpingectomy - removal of tube for ectopic pregnancy
5. In vitro fertilization (IVF) - bypasses tube

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Q39. Pelvic Floor

1. Levator ani (main component) - 3 parts:
   • Puborectalis - forms a sling around anorectal junction; maintains anorectal angle
   • Pubococcygeus - from pubis to coccyx; supports bladder, prostate/vagina, rectum
   • Iliococcygeus - from ilium to coccyx; largest
2. Coccygeus (ischiococcygeus) - from ischial spine to coccyx and sacrum
3. Perineal body (central tendon) - fibromuscular node at center of perineum; meeting point of 9 muscles

1. Supports pelvic organs
2. Controls sphincters
3. Maintains anorectal angle (continence)
4. Resists raised intra-abdominal pressure

1. Pelvic floor dysfunction - after childbirth; incontinence, prolapse
2. Perineal tear - during delivery; extends into perineal body; 1st to 4th degree
3. Episiotomy - mediolateral incision through perineal body + bulbospongiosus
4. Levatorplasty - surgical repair of torn levator ani
5. Levator ani syndrome - chronic pelvic pain from spasm

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Q40. Sacroiliac Joint

• Actually a diarthrosis anteroinferiorly (hyaline cartilage) and a fibrous joint posterosuperiorly (interosseous ligaments)

• Anterior sacroiliac ligament - thin, on anterior surface
• Posterior sacroiliac ligament - strong; on posterior surface
• Interosseous sacroiliac ligament - strongest ligament in body; between rough surfaces posterior to joint
• Accessory ligaments:
  • Iliolumbar ligament (L5 transverse process to iliac crest)
  • Sacrospinous ligament (sacrum to ischial spine) - converts greater sciatic notch to greater sciatic foramen
  • Sacrotuberous ligament (sacrum to ischial tuberosity) - converts lesser sciatic notch to lesser sciatic foramen

1. Sacroiliitis - inflammation; in ankylosing spondylitis (bilateral), Reiter's syndrome
2. Pelvic ring fracture - may disrupt sacroiliac joints
3. Pregnancy - progesterone relaxes ligaments → increased mobility → pelvic pain
4. Sacroiliac joint injection - therapeutic/diagnostic
5. Osteitis condensans ilii - dense bone on iliac side; seen in multiparous women

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Q41. Pelvic Walls and Floor

• Sacral promontory (posterior)
• Iliopectineal lines (lateral)
• Symphysis pubis (anterior)

• Pubic arch (anterior)
• Ischial tuberosities (lateral)
• Sacrum/coccyx (posterior)

• Origin: Anterior surface of sacrum (S2-4)
• Exits through greater sciatic foramen
• Divides foramen into above (superior gluteal nerve and vessels) and below (sciatic nerve, inferior gluteal nerve, pudendal nerve, nerve to obturator internus, nerve to quadratus femoris, posterior cutaneous nerve of thigh)

• Lines lateral pelvic wall; exits through lesser sciatic foramen
• Forms lateral wall of ischiorectal fossa (within Alcock's canal containing pudendal nerve)

1. Piriformis syndrome - sciatic nerve compression
2. Pelvic fracture - injury to pelvic structures
3. False vs true pelvis - obstetric importance
4. Pelvic measurements (obstetric conjugates)

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Q42. Ischiorectal (Ischioanal) Fossa

• On lateral wall of ischioanal fossa within the obturator internus fascia
• Contains: Pudendal nerve, internal pudendal artery and vein

• Ischiorectal fat (adipose tissue - fills the space)
• Inferior rectal nerve and vessels (branch of pudendal nerve)
• Perineal branch of S4
• Scrotal/labial posterior nerve branches
• Pudendal nerve in Alcock's canal (lateral wall)

1. Ischiorectal abscess - infection of ischioanal fat; severe perianal pain; fluctuant swelling; surgical drainage
2. Fistula-in-ano - track from anal canal to skin; may pass through sphincters (Parks' classification)
3. Both fossae communicate posteriorly behind anococcygeal body → horseshoe abscess
4. Pudendal nerve block - in Alcock's canal; anesthesia for perineum in obstetrics
5. The abundant fat allows expansion in defecation but also allows abscess to track widely

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Q43. Anal Canal

• Internal anal sphincter (IAS): Smooth muscle; involuntary; continuation of circular muscle of rectum; supplied by sympathetic (contraction) and parasympathetic (relaxation)
• External anal sphincter (EAS): Skeletal muscle; voluntary; 3 parts (subcutaneous, superficial, deep); supplied by pudendal nerve (S2,3,4)
• Puborectalis: Sling around anorectal junction maintaining 90° angle

1. Hemorrhoids - anal cushions at 3, 7, 11 o'clock positions (right anterolateral, right posterolateral, left lateral). Internal hemorrhoids (above pectinate line) - painless bleeding. External hemorrhoids (below pectinate line) - painful
2. Fissure-in-ano - tear at posterior midline (ischemic area - poor blood supply); spasm of IAS
3. Fistula-in-ano - Parks' classification based on relation to sphincters
4. Carcinoma: Above pectinate line → adenocarcinoma (→ internal iliac nodes); below → squamous cell carcinoma (→ inguinal nodes); anal margin → squamous cell
5. Anal manometry and defecography - investigations
6. Hirschsprung's disease - absence of ganglia in Auerbach's/Meissner's plexuses to internal sphincter and above

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Q44. Male Perineum and External Genitalia

• Bulb of penis + bulbospongiosus muscle
• Crus of penis + ischiocavernosus muscle
• Superficial transverse perineal muscles
• Perineal nerves and vessels

• Membranous urethra + external urethral sphincter
• Bulbourethral (Cowper's) glands → ducts open into spongy urethra
• Deep transverse perineal muscles
• Internal pudendal artery (continuation into bulbourethral arteries)
• Dorsal nerve of penis

• 3 cylindrical bodies: 2 corpora cavernosa (main erectile tissue) + 1 corpus spongiosum (surrounds urethra; expanded posteriorly as bulb, anteriorly as glans)
• Buck's fascia - deep fascia of penis
• Colles' fascia - continuation of Scarpa's fascia into perineum
• Dartos - smooth muscle in scrotal wall

1. Urethral injury in straddle - bulbous urethra; urine in superficial pouch → Colles' fascia → scrotum → perineum → abdominal wall (Scarpa's) - does NOT spread to thigh (fascia lata attachment)
2. Priapism - persistent erection; medical emergency
3. Peyronie's disease - fibrosis of corpora cavernosa
4. Phimosis/paraphimosis - foreskin issues

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Q45. Female Perineum

• Clitoris (body, crura covered by ischiocavernosus)
• Bulb of vestibule (paired) + bulbospongiosus
• Greater vestibular (Bartholin's) glands - lie on either side of vaginal orifice; open by ducts in the groove between labia minora and hymen; homologue of Cowper's glands; secrete lubricating fluid

• External urethral sphincter
• Deep transverse perineal muscle
• Pudendal vessels

1. Bartholin's gland cyst/abscess - duct obstruction; 4 o'clock/8 o'clock positions
2. Vulvar carcinoma - squamous cell; spreads to superficial inguinal nodes
3. Episiotomy - mediolateral; through perineal body
4. Perineal tear classification:
   • 1st degree: Skin only
   • 2nd degree: Skin + perineal body muscles
   • 3rd degree: Above + external anal sphincter
   • 4th degree: All above + IAS + rectal mucosa

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SECTION B: SHORT NOTES - ABDOMEN & PELVIS (All 50)

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• Junction of medial 2/3 and lateral 1/3 of line from umbilicus to right ASIS
• Surface marking of base of appendix
• Point of maximum tenderness in acute appendicitis
• Site of gridiron incision for appendicectomy
• Rovsing's sign: pressure on left iliac fossa causes pain at McBurney's point

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• Remnant of vitello-intestinal (omphalomesenteric) duct
• Rule of 2s: 2% population; 2 feet (60 cm) from ileocaecal junction; 2 inches long; 2 types of ectopic tissue (gastric most common, also pancreatic); 2:1 male:female; presents before 2 years
• True diverticulum (all 3 layers of gut wall)
• Contains ectopic gastric mucosa → secretes acid → peptic ulceration → bleeding (most common complication in children)
• Other complications: Diverticulitis, intestinal obstruction (volvulus around fibrous band to umbilicus), intussusception
• Littre's hernia = Meckel's diverticulum within a hernia sac
• Diagnosis: Technetium-99m pertechnetate scan

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• Also called hepatocystic triangle
• Boundaries:
  • Above: Inferior surface of liver (right hepatic duct by some)
  • Below: Cystic duct
  • Left/Medial: Common hepatic duct
• Contents: Cystic artery (usually from right hepatic artery), cystic lymph node (Lund's node), right hepatic artery
• Surgical importance: Must identify cystic artery within Calot's triangle before ligation during cholecystectomy to prevent bile duct injury
• Variations of cystic artery are common - must be careful

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• Normal portal pressure: 5-10 mmHg; portal hypertension when >12 mmHg
• Causes:
  • Pre-hepatic: Portal vein thrombosis
  • Hepatic (sinusoidal): Cirrhosis (most common - alcohol, viral hepatitis)
  • Post-hepatic: Budd-Chiari syndrome, right heart failure
• Effects: Esophageal varices, caput medusae, hemorrhoids (internal), splenomegaly, ascites
• Portocaval anastomoses (5 sites):
  1. Lower esophagus (left gastric → azygos) → esophageal varices - most dangerous
  2. Umbilicus (paraumbilical → superficial epigastric) → caput medusae
  3. Rectum (superior rectal → middle/inferior rectal) → internal hemorrhoids
  4. Retroperitoneum (veins of Retzius - mesenteric to renal/lumbar)
  5. Bare area of liver (hepatic veins to diaphragmatic veins)
• Treatment: TIPS, portosystemic shunt, propranolol (reduces portal pressure), banding of varices

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• Visceral pain is poorly localized and referred to dermatomes corresponding to spinal cord level of organ:
  • T5-6: Esophagus
  • T6-9: Stomach, duodenum, liver, gallbladder → epigastric
  • T10: Appendix (early), small intestine → periumbilical
  • T11-12: Colon
  • L1: Ureter, gonads → groin, scrotum/labia
  • C3,4,5: Diaphragm → shoulder tip (phrenic nerve)
• Classic examples:
  • Appendicitis: Early periumbilical (T10 visceral) → later RIF (somatic)
  • Gallbladder: Epigastric + right shoulder (phrenic irritation)
  • Ureteric colic: Loin to groin + scrotum
  • Ruptured spleen: Left shoulder tip (Kehr's sign)
  • Diaphragmatic irritation: Shoulder tip

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• Morphological lobes (4): Right, left, quadrate, caudate
• Surgical (Couinaud) segmentation (8 segments): Based on hepatic artery and portal vein supply + hepatic vein drainage
  • Segments I: Caudate lobe
  • Segments II-IV: Left lobe (left portal pedicle)
  • Segments V-VIII: Right lobe (right portal pedicle)
  • Segments II-III: Left lateral sector
  • Segment IV: Left medial sector (quadrate)
• Surgical significance: Each segment is an independent functional unit → can be individually resected (segmentectomy)
• Middle hepatic vein divides right and left lobes (Cantlie's line - from gallbladder fossa to IVC)
• Hepatectomy is based on Couinaud segments
• Right hepatectomy = segments V-VIII; Left hepatectomy = II-IV

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• Only communication between greater sac and lesser sac
• Boundaries:
  • Anterior: Free edge of lesser omentum (contains portal vein, hepatic artery, bile duct - "Pringle's")
  • Posterior: IVC
  • Superior: Caudate lobe of liver
  • Inferior: 1st part of duodenum
• Pringle's maneuver: Finger in foramen + thumb on anterior lesser omentum → compresses portal triad → controls intraoperative liver hemorrhage
• Internal herniation through epiploic foramen can occur (rare surgical emergency)

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• The stomach bed is formed by structures forming the posterior wall of the lesser sac:
  1. Left suprarenal gland
  2. Upper part of left kidney
  3. Splenic artery (along upper border of pancreas)
  4. Pancreas (body and tail)
  5. Transverse mesocolon
  6. Transverse colon
  7. Spleen
• Clinical: Posterior gastric ulcer perforates into lesser sac → lesser sac collection (not free peritoneal) → may erode splenic artery

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• Compression of the 3rd (horizontal) part of duodenum between SMA anteriorly and aorta posteriorly
• Causes: Severe weight loss (loss of mesenteric/retroperitoneal fat), prolonged supine position, body cast syndrome
• Features: Postprandial vomiting (bilious), epigastric pain, weight loss, intermittent obstruction
• Investigations: Upper GI series (barium), CT with contrast
• Treatment: Conservative (small frequent feeds, prone position, TPN) or surgical (duodenojejunostomy)
• The angle between aorta and SMA normally 25-60°; reduced in SMA syndrome

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• Compression of the left renal vein between the superior mesenteric artery (anteriorly) and the aorta (posteriorly) - like a nut being cracked
• Results in: Left renal venous hypertension → hematuria (blood from left kidney into urine), left flank pain, proteinuria, left varicocele (since left testicular/ovarian vein drains into left renal vein)
• Diagnosis: Doppler ultrasound, CT angiography
• Can be anterior (SMA-Ao compression) or posterior (aorta and vertebral body)
• Treatment: Conservative; stenting; surgical transposition of left renal vein

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• Collection of pus in the psoas major muscle sheath
• Primary: Hematogenous spread (Staphylococcal bacteremia)
• Secondary (more common): Spread from adjacent structures:
  • Vertebral osteomyelitis/TB (Pott's disease) → cold abscess tracking down psoas sheath
  • Crohn's disease, appendicitis, renal infection, iliac lymphadenitis
• Presentation: Hip flexion contracture (fixed flexion deformity), pain in hip/back/thigh, fever
• Path of tracking: Along psoas → under inguinal ligament → lateral to femoral vessels → presents in femoral triangle or on medial thigh
• Diagnosis: CT scan
• Treatment: CT-guided drainage + antibiotics ± surgical drainage

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• Protrusion of extraperitoneal fat or abdominal contents through femoral ring into femoral canal
• More common in females (wider femoral ring due to wider pelvis)
• Located below and lateral to pubic tubercle (vs inguinal hernia which is above and medial)
• Femoral triangle boundaries: Inguinal ligament (base), sartorius (lateral), adductor longus (medial); Floor: iliopsoas + pectineus + adductor longus; Roof: fascia lata
• Femoral canal boundaries: Inguinal ligament (anterior), pectineal ligament (posterior), femoral vein (lateral), lacunar ligament (medial)
• High risk of strangulation due to rigid unyielding femoral ring
• Treatment: McVay (Cooper's ligament) repair or laparoscopic (TEP/TAPP)

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• Defined by:
  • Medial: Lateral border of rectus abdominis
  • Lateral: Inferior epigastric artery
  • Inferior: Inguinal ligament
• The floor of this triangle is the posterior wall of the inguinal canal (transversalis fascia + conjoint tendon)
• Direct inguinal hernia passes through this triangle
• Applied: Weakness here (after TURP, previous surgery, old age, obesity) → direct hernia

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• 3 arteries: Testicular, artery to vas deferens (from inferior vesical), cremasteric (from inferior epigastric)
• 3 nerves: Genital branch of genitofemoral, sympathetics around testicular artery, ilioinguinal (not inside fascia)
• 2 veins: Pampiniform plexus (testicular veins - 10-12 veins)
• 1 lymphatic: Lymphatics to para-aortic nodes
• Vas deferens (ductus deferens)
• Processus vaginalis remnant

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• Gubernaculum = cord-like structure in fetus guiding descent of gonad
• In male: Guides testis from retroperitoneum through inguinal canal into scrotum; after birth, involutes
• In female:
  • Upper part → ligament of ovary (connects ovary to uterus)
  • Lower part → round ligament of uterus (from uterus through inguinal canal to labium majus)
  • Ovary remains in pelvis (tethered by Müllerian duct - cannot fully descend)

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• Peritoneal diverticulum extending through inguinal canal into scrotum alongside testis during descent
• Normal fate: Obliterated after birth (around 1st year); leaves only tunica vaginalis around testis
• Abnormal persistence:
  • Complete patency → congenital indirect inguinal hernia
  • Partial patency → hydrocele (communicating or non-communicating)
  • Encysted processus vaginalis → hydrocele of cord
• Hydrocele types:
  • Vaginal hydrocele: Most common; fluid in tunica vaginalis
  • Congenital hydrocele: Patent processus; communicates with peritoneal cavity
  • Encysted hydrocele of cord: Patency in middle segment
  • Infantile hydrocele: Extends to internal ring but not into peritoneal cavity

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• Rectovesical pouch (between bladder and rectum) - most dependent in erect male

• Vesicouterine pouch (between bladder and uterus - anteriorly) - shallower
• Rectouterine pouch (pouch of Douglas - between uterus and rectum) - most dependent in female erect

• Fluid, blood, pus collects here (most dependent part of female pelvis)
• Ruptured ectopic pregnancy → blood in pouch of Douglas
• Pelvic peritonitis → tenderness on posterior vaginal fornix
• Culdocentesis - needle through posterior vaginal fornix into Douglas's pouch for diagnosis
• Pelvic abscess drained through posterior fornix (colpotomy)

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• Origin: S2, S3, S4
• Course:
  • Exits pelvis through greater sciatic foramen (below piriformis)
  • Crosses ischial spine (sacrospinous ligament)
  • Enters perineum through lesser sciatic foramen
  • Travels in Alcock's canal (pudendal canal) on obturator internus fascia
• Branches:
  • Inferior rectal nerve → external anal sphincter + perianal skin
  • Perineal nerve → superficial perineal muscles, scrotum/labia
  • Dorsal nerve of penis/clitoris → erectile tissue sensation
• Pudendal nerve block: Transvaginal or transperineal approach at ischial spine; used in obstetrics for perineal anesthesia

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• Origin: L2, L3, L4 (posterior divisions)
• Course:
  • Emerges from medial border of psoas
  • Crosses pelvic brim (lateral to ureter and ovary/vas deferens)
  • Passes through obturator foramen (obturator canal)
  • Divides into anterior and posterior branches
• Branches:
  • Anterior: Adductor longus, brevis, gracilis; skin of medial thigh
  • Posterior: Obturator externus, adductor magnus (part)
  • Articular branch to hip and knee joints
• Applied:
  • Obturator hernia → compresses nerve → pain along medial thigh to knee (Howship-Romberg sign)
  • Hip disease → referred pain to medial knee (obturator articular branch)
  • Obturator nerve injury in gynecological surgery or pelvic fracture

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• Formed by: Ventral rami of L4 (lower part) + L5
• Significance: Connects lumbar plexus to sacral plexus
• Passes over ala of sacrum, crosses pelvic brim anterior to sacroiliac joint
• Joins S1 to form sciatic nerve (in sacral plexus)
• Applied: Compression in obstructed labor → foot drop (lumbosacral trunk neuropathy); also damaged in pelvic fractures at the sacroiliac joint level

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• Triangular fibromuscular sheet filling the anterior part of the pelvic outlet (urogenital triangle)
• Attached to ischiopubic rami on each side; posterior free border
• Male contents of deep perineal pouch (within):
  • External urethral sphincter (rhabdosphincter)
  • Deep transverse perineal muscles
  • Bulbourethral (Cowper's) glands
  • Membranous urethra
  • Internal pudendal vessels
  • Dorsal nerves of penis
• Female contents:
  • External urethral sphincter
  • Compressor urethrae and sphincter urethrovaginalis
  • Urethra and vagina pass through it

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• Fibromuscular node at center of perineum, between vagina (or bulbous urethra) and anal canal
• 9 muscles attached:
  1. External anal sphincter
  2. Bulbospongiosus (bilateral)
  3. Superficial transverse perineal (bilateral)
  4. Deep transverse perineal (bilateral)
  5. Levator ani (puborectalis) fibers
  6. External urethral sphincter (some fibers)
• Clinical significance:
  • Key structure maintaining pelvic floor integrity
  • Destroyed in perineal tears during childbirth → incontinence, prolapse
  • Episiotomy cuts through perineal body
  • Perineal repair must restore perineal body

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• Rectovesical: Between bladder and rectum in males; most dependent peritoneal space in erect male
• Rectouterine (Douglas): Between posterior uterus/posterior vaginal fornix and anterior rectum; most dependent space in erect female
• Culdocentesis: Needle puncture of posterior fornix to enter Douglas's pouch; detects blood (ectopic), pus (PID/appendicitis), or fluid (ascites)
• Drainage of pelvic abscess: Through posterior fornix (colpotomy)

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• Blood in Douglas = ruptured ectopic pregnancy, ruptured ovarian cyst, splenic rupture
• Pus = PID (tubo-ovarian abscess), pelvic peritonitis
• Fluid = ascites, peritoneal carcinomatosis
• Endometriosis involving Douglas pouch → dyspareunia, dysmenorrhea
• Frozen pelvis = obliteration of Douglas pouch by endometriosis/malignancy
• Krukenberg tumor - metastases to ovary from gastric cancer; via peritoneal route including Douglas pouch

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1. Cardinal (Mackenrodt's/transverse cervical) ligaments - most important; from cervix to lateral pelvic wall; thickening of base of broad ligament
2. Uterosacral ligaments - from cervix to sacrum (S2-4); maintain anteversion

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• Origin: Parasympathetic; S2, S3, S4 (ventral rami)
• Course: Arise from sacral spinal cord; pass directly to hypogastric plexus and pelvic organs
• Functions:
  • Erection (penis/clitoris) - "POINT"
  • Detrusor contraction (voiding)
  • Inhibition of internal anal sphincter (defecation)
  • Vasodilation of pelvic viscera
  • Descending colon and sigmoid colon motility
• Applied: Damage in abdominoperineal resection, radical hysterectomy, TURP → impotence, incontinence

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• Continuation of aortic plexus; sympathetic (T10-L2)
• Superior hypogastric plexus: Presacral nerve; in front of bifurcation of aorta
• Inferior hypogastric (pelvic) plexus: On lateral pelvic wall; mixed (sympathetic from superior hypogastric + parasympathetic from pelvic splanchnic nerves S2-4)
• Supplies: Rectum, urinary bladder, prostate/uterus, genitalia
• Applied: Damage during colorectal surgery, hysterectomy, prostatectomy → bladder/bowel/sexual dysfunction

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• Surgical division of superior hypogastric plexus (presacral nerve)
• Indication: Intractable dysmenorrhea, endometriosis, central pelvic pain
• Nerve lies in front of sacral promontory
• Effects: Relieves midline pelvic pain; preserves lateral pelvic sensation
• Complications: Constipation, bladder dysfunction if lateral hypogastric plexus also damaged

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• Curved line on posterior wall of rectus sheath
• Located midway between umbilicus and pubic symphysis
• Marks the lower limit of the posterior layer of the rectus sheath
• Below this line, ALL three aponeuroses pass anterior to rectus abdominis → posterior wall = transversalis fascia only
• Applied:
  • Spigelian hernia occurs at or just below arcuate line (along lateral border of rectus sheath)
  • Hematoma below arcuate line can spread freely (no posterior wall containment)
  • Landmark in rectus sheath blocks (regional anesthesia)

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• Hernia through Spigelian fascia (aponeurosis of transversus abdominis) at its lateral border (Spigelian line)
• Located at or just below arcuate line (where transversalis fascia is thin)
• Features: Usually small, interparietal (between muscular layers); often missed clinically
• Presents as an intermittent abdominal swelling lateral to rectus; high risk of strangulation
• Diagnosis: Ultrasound or CT scan
• Treatment: Surgical repair

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• Through the umbilical ring (closed after birth)
• Common in infants/children; usually closes spontaneously by 2-3 years
• Associated with Down syndrome, Beckwith-Wiedemann
• Usually requires no surgery if small; repair if persists beyond 3-4 years

• Through linea alba just above or below the umbilicus (not through umbilical ring itself)
• Common in obese, multiparous women
• Contents: Omentum, bowel; high risk of strangulation
• Treatment: Always surgical repair (Mayo's repair - overlapping the aponeurosis)

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• Sympathetic (T11-L2) via hypogastric plexus → relaxes detrusor, contracts internal sphincter (storage)
• Parasympathetic (S2-4) via pelvic splanchnic nerves → contracts detrusor, relaxes internal sphincter (voiding)
• Somatic (S2-4 via pudendal) → external urethral sphincter (voluntary control)

1. Bladder fills → stretch receptors in bladder wall activated at ~150 mL
2. Afferents via pelvic splanchnic nerves to sacral cord (S2-4)
3. Reflex arc → parasympathetic outflow → detrusor contraction
4. Cortical inhibition (pontine micturition center) prevents voiding until socially appropriate
5. Voluntary relaxation of external sphincter + detrusor contraction → voiding
6. Urge to void felt around 300 mL; maximum capacity ~500 mL

• Upper motor neuron lesion (above S2): Spastic neurogenic bladder; reflex emptying
• Lower motor neuron lesion (S2-4 or below): Flaccid neurogenic bladder; overflow incontinence

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• Tunica albuginea: Dense fibrous coat around each corpus cavernosum; helps maintain erection
• Buck's fascia (deep fascia of penis): Surrounds both corpora cavernosa and corpus spongiosum together; deep to superficial fascia
• Dartos fascia (superficial fascia of penis): Loose, no fat; continuous with Scarpa's fascia of abdomen and Colles' fascia of perineum
• Applied: Bulbar urethral rupture → urine tracks under Colles' fascia → scrotum, penis, lower anterior abdominal wall (Scarpa's fascia); does NOT spread to thigh (Scarpa's fascia attached to fascia lata below)

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• Testicular carcinoma → para-aortic node enlargement (NOT inguinal nodes)
• Inguinal lymphadenopathy in testicular cancer → scrotal skin involvement or after orchidopexy (scar disrupts normal drainage)
• Squamous carcinoma of scrotal skin → superficial inguinal nodes

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• Testis develops retroperitoneally at L2 (gonadal ridge) from genital ridge
• Stages:
  • Transabdominal phase: Weeks 10-15; testis descends from L2 to inguinal region; driven by Müllerian inhibiting factor (MIF/AMH) and insulin-3 (INSL3); gubernaculum swells
  • Inguinoscrotal phase: Weeks 26-35; testis passes through inguinal canal into scrotum; driven by androgens + genitofemoral nerve (calcitonin gene-related peptide CGRP)
• Processus vaginalis precedes testis
• Testis in scrotum by 34th week gestation
• Right testis descends later

• Cryptorchidism (undescended testis): Most common congenital genital anomaly (1% full-term boys); right > left; increased risk of malignancy (especially if abdominal); treated by orchidopexy before age 2
• Ectopic testis: Testis outside normal pathway (perineum, femoral, superficial inguinal pouch)
• Retractile testis: Normal; cremasteric reflex brings testis into inguinal canal

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• Superior mesenteric vein (drains small intestine, ascending and transverse colon)
• Splenic vein (drains spleen, stomach; receives inferior mesenteric vein)
• Left gastric (coronary) vein
• Right gastric vein
• Cystic vein
• Paraumbilical veins
• Note: Inferior mesenteric vein drains into splenic vein (usually)

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• Area on diaphragmatic surface of right lobe not covered by peritoneum
• Between anterior and posterior layers of coronary ligament
• Boundaries: Anterior coronary ligament (front), posterior coronary ligament (back), right triangular ligament (right)
• Clinical significance:
  • Bare area is in direct contact with diaphragm → spread of infection between liver and pleural cavity
  • Subphrenic abscess may track to pleural space
  • Liver can be drained without opening peritoneal cavity through bare area
  • Portal hypertension: Veins of bare area (systemic) anastomose with portal tributaries (5th portocaval site)

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• Obliterated left umbilical vein
• Runs in lower free border of falciform ligament
• From umbilicus to left branch of portal vein
• Applied: Can be recannalized in portal hypertension (caput medusae); used in Rex shunt (mesentericoumbilical shunt for portal hypertension in children)

• Obliterated ductus venosus
• Fibrous cord in a fissure on visceral surface of liver between left lobe and caudate lobe
• In fetus: ductus venosus connected left umbilical vein to IVC, bypassing liver
• Applied: Caudate lobe bounded on left by ligamentum venosum fissure

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• Spaces between diaphragm and upper abdominal organs

• Morrison's pouch is clinically the most important: Most dependent space in supine position; ascitic fluid/blood/pus collects here first → drained by intercostal drain or guided drainage
• Subphrenic abscess - after perforated peptic ulcer, appendicitis; presents with hiccough (diaphragmatic irritation), shoulder tip pain, pyrexia

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• Junction of duodenum and jejunum
• Located at left of L2 vertebra (at level of transpyloric plane laterally)
• Suspended by ligament of Treitz (suspensory muscle/ligament of duodenum) - fibromuscular band from right crus of diaphragm to DJF
• Marks the division between upper GI and lower GI bleeding
• Applied:
  • Volvulus at DJF
  • Upper GI endoscopy reaches DJF
  • Paraduodenal hernias (Treitz's hernia) at DJF
  • Surgical landmark: "DJF is where bowel hangs from its root"

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• Above pectinate line: Superior rectal vein → inferior mesenteric vein → portal vein (site of internal hemorrhoids)
• Below pectinate line: Inferior rectal vein → pudendal vein → internal iliac → systemic

• Internal hemorrhoids at 3, 7, 11 o'clock (sites of anastomosis between superior and inferior rectal veins)
• Hemorrhoidectomy spares skin bridges at above positions

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• Kidneys and adrenal glands
• Ureters
• Aorta, IVC
• Duodenum (2nd, 3rd, 4th parts)
• Ascending and descending colon
• Rectum (partially)

• Pancreas (body, tail; head is within C of duodenum)
• Ascending colon
• Descending colon
• Duodenum (2nd-4th parts)
• Liver (bare area)
• Extra: Left and right colon during gut rotation/fixation

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1. Renal vein (most anterior)
2. Renal artery (behind vein)
3. Renal pelvis (most posterior)
4. Lymphatics
5. Sympathetic nerves (with artery)

• Typically one renal artery (may be 2 in ~20%), one renal vein per kidney
• Right renal vein is short; left is longer
• Renal pelvis at hilum → ureter exits inferomedially

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• Origin: C3, C4, C5 (C4 is main)
• Course:
  • Descends on scalenus anterior
  • Crosses 1st part subclavian artery
  • Enters thorax
  • Right phrenic: Through caval opening (T8)
  • Left phrenic: Pierces left dome of diaphragm
• Branches: Motor to diaphragm + sensory to central tendon (pericardium, diaphragmatic pleura and peritoneum)
• Applied:
  • C3,4,5 - "keeps the diaphragm alive"
  • Referred pain to shoulder tip (C4 dermatome) from diaphragmatic irritation (blood, pus, phrenic nerve irritation)
  • Phrenic nerve crush/palsy - used previously for pulmonary TB (to collapse lung)
  • Injury in cervical spine injury → respiratory failure
  • Hiccough: Irritation of phrenic/vagus nerve

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• Muscular pillars arising from lumbar vertebrae attaching diaphragm to posterior abdominal wall
• Right crus: From L1, L2, L3 (larger); fibers form loop around esophageal hiatus; acts as external sphincter
• Left crus: From L1, L2 (smaller)
• Median arcuate ligament: Bridge connecting right and left crura over aortic hiatus (T12)
• Applied:
  • Hemiazygos vein passes through left crus
  • Splanchnic nerves pierce crura
  • Median arcuate ligament syndrome (MALS): Compression of celiac trunk by median arcuate ligament → postprandial angina
  • In CDH (Bochdalek) - failure of pleuroperitoneal membrane (not crus) but close relationship

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• A funnel-shaped fascial sheath formed by a prolongation of the transversalis fascia (anterior wall) and iliac fascia (posterior wall) into the thigh
• Encloses: Femoral artery (lateral compartment), femoral vein (middle compartment), femoral canal (medial compartment)
• Femoral canal: Medial compartment; normally contains only loose areolar tissue and lymph node (Cloquet's node); 1.25 cm long
• Femoral ring (entrance to canal): Bounded by femoral vein (lateral), lacunar ligament (medial - sharp edge), inguinal ligament (anterior), pectineal ligament/Cooper's (posterior)
• Femoral hernia enters femoral ring → passes through femoral canal → emerges below inguinal ligament as a swelling in the femoral triangle
• Cloquet's (Rosenmüller's) node in femoral canal receives lymph from vulva/perineum; enlargement may be mistaken for femoral hernia

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ALL LAQs - 1st YEAR MBBS ANATOMY

Abdomen & Pelvis + Lower Limb

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PART 1: ABDOMEN & PELVIS LAQs (45 Questions)

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ANTERIOR ABDOMINAL WALL

• Deep (internal) inguinal ring: Oval defect in transversalis fascia; 1.25 cm above midpoint of inguinal ligament; lateral to inferior epigastric artery
• Superficial (external) inguinal ring: Triangular defect in external oblique aponeurosis; above and medial to pubic tubercle

• Male: Spermatic cord + ilioinguinal nerve
• Female: Round ligament of uterus + ilioinguinal nerve

1. Indirect inguinal hernia - enters deep ring lateral to inferior epigastric artery; traverses full canal length; exits at superficial ring; acquires all layers of spermatic cord as coverings
2. Direct inguinal hernia - pushes through posterior wall (Hesselbach's triangle); medial to inferior epigastric artery; does NOT traverse deep ring
3. Hydrocele - patent processus vaginalis with fluid accumulation
4. Cremasteric reflex - L1 spinal cord level testing
5. Oblique direction = protective mechanism; raised intra-abdominal pressure closes canal

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1. Rectus abdominis muscle
2. Pyramidalis muscle (inconstant; in front of lower rectus)
3. Superior epigastric artery (from internal thoracic)
4. Inferior epigastric artery (from external iliac)
5. Superior and inferior epigastric veins
6. Lower 5 intercostal nerves (T7-T11) + subcostal nerve (T12)
7. Lymphatics

1. Rectus sheath hematoma - injury to epigastric vessels; below arcuate line spreads freely; above = confined
2. Midline incision through linea alba - bloodless, widely used
3. Paramedian incision - through rectus sheath
4. Spigelian hernia - at lateral border at arcuate line level
5. Rectus sheath block - regional anesthesia for abdominal surgery

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• Femoral and inguinal hernias
• Femoral artery cannulation landmark (midinguinal point)
• Sharp lacunar ligament edge strangulates femoral hernias

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1. Skin
2. Superficial fascia - Camper's (fatty layer)
3. Deep layer of superficial fascia - Scarpa's (membranous; continuous with dartos, Colles' fascia)
4. External oblique (and aponeurosis) - fibers downward and medially
5. Internal oblique (and aponeurosis) - fibers upward and medially
6. Transversus abdominis (and aponeurosis) - horizontal fibers; deepest flat muscle
7. Transversalis fascia
8. Extraperitoneal fat
9. Parietal peritoneum

• T7-T12: Lower 6 intercostal nerves and subcostal nerve (segmental)
• L1: Iliohypogastric (skin above pubis) and ilioinguinal (groin and scrotum/labia)
• Dermatome reference: T10 = umbilicus; T4 = nipple level

• Superior epigastric artery (from internal thoracic)
• Inferior epigastric artery (from external iliac)
• Superficial epigastric, superficial circumflex iliac (from femoral)
• Deep circumflex iliac (from external iliac)
• Posterior intercostal arteries (T7-T11)
• Subcostal artery (T12)

• Caput medusae - dilated paraumbilical veins in portal hypertension
• Surgical incisions: Midline, paramedian, gridiron (McBurney), Pfannenstiel, Kocher's, Rutherford-Morrison
• Herniation sites along weak areas

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PERITONEUM

• Parietal peritoneum: Lines walls; somatic nerve supply (well localized pain)
• Visceral peritoneum: Covers organs; autonomic nerve supply (poorly localized, referred pain)
• Peritoneal cavity: Potential space containing ~50 mL serous fluid (lubrication)
• Greater sac: Main peritoneal cavity
• Lesser sac (omental bursa): Behind stomach/lesser omentum; communicates via epiploic foramen

• Hepatorenal (Morrison's pouch): Between right lobe liver and right kidney; most dependent supine
• Rectouterine pouch (Douglas): Most dependent female erect
• Rectovesical pouch: Most dependent male erect
• Subphrenic spaces (right and left)
• Paracolic gutters (right and left)

• Peritoneal membrane used as a dialyzing membrane (acts as a semi-permeable membrane)
• Dialysate (hypertonic glucose solution) instilled via permanent catheter (Tenckhoff catheter) into peritoneal cavity
• Waste products and water removed by osmosis and diffusion across the peritoneum
• Dialysate drained after dwell time; exchanged 3-4 times daily (CAPD - continuous ambulatory peritoneal dialysis)
• Advantages: Home treatment, continuous, gentle
• Complications: Peritonitis (most common), catheter blockage, herniation

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• Anterior: Free border of lesser omentum (portal vein, hepatic artery, bile duct)
• Posterior: IVC
• Superior: Caudate lobe of liver
• Inferior: 1st part of duodenum (duodenocolic ligament)

• Main vestibule (behind lesser omentum)
• Splenic recess (extends into gastrosplenic ligament toward spleen)
• Superior recess (behind caudate lobe)

1. Pancreatic pseudocyst forms in lesser sac (post pancreatitis)
2. Posterior gastric perforation → fluid collects in lesser sac (not free peritoneum) → diagnostic dilemma
3. Pringle's maneuver - finger in epiploic foramen to compress portal triad
4. Surgical access to pancreas - through gastrocolic omentum
5. Lesser sac abscess - secondary to pancreatitis

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• Develops from dorsal mesogastrium
• As stomach rotates, dorsal mesogastrium swings left and downward
• Forms a double fold that descends as an apron in front of small intestine
• Later fuses with transverse mesocolon posteriorly

• Upper: Greater curvature of stomach and first 2 cm of duodenum
• Lower: Hangs freely; fuses with anterior surface of transverse colon

• Right gastroepiploic (gastro-omental) artery: From gastroduodenal artery (celiac axis)
• Left gastroepiploic artery: From splenic artery
• These anastomose along greater curvature

1. "Policeman of the abdomen" - migrates to sites of inflammation/infection; walls off peritonitis, appendicitis, perforations
2. Fat storage and insulation of abdominal viscera
3. Immune function - milky spots (aggregates of lymphocytes and macrophages)
4. Limits spread of infection by adhesion and physical barrier
5. Omentoplasty - fills dead spaces in surgery

1. Graham patch omentoplasty - seal of perforated duodenal ulcer
2. Omental torsion - rare acute abdomen
3. Omental cake - peritoneal metastasis coating omentum (ovarian, gastric carcinoma)
4. Omentectomy in ovarian cancer staging
5. Used to revascularize areas in reconstructive surgery

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• Superior mesenteric artery and all its branches
• Superior mesenteric vein tributaries
• 200+ mesenteric lymph nodes + lymphatics (lacteals absorb fat → chyle)
• Autonomic nerve plexuses (around SMA)
• Variable amounts of fat (more in ileum)

1. Mesenteric ischemia - SMA occlusion; severe abdominal pain; "pain out of proportion to examination"; surgical emergency
2. Volvulus - bowel twists on its mesentery → obstruction + ischemia
3. Mesenteric adenitis - lymph node enlargement (viral) → mimics appendicitis
4. Short bowel syndrome - after extensive mesenteric resection
5. Mesenteric cysts - lymphatic or enteric origin; can cause obstruction
6. Carcinoid syndrome - from mesenteric lymph node secondaries of carcinoid

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STOMACH

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• Left gastric artery ligation in gastrectomy: Must be identified and ligated at its origin from celiac trunk
• Right gastroepiploic artery used as graft in coronary bypass surgery
• Posterior gastric perforation/ulcer - erodes splenic artery → life-threatening hemorrhage
• Posterior duodenal ulcer - erodes gastroduodenal artery → massive hematemesis

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SMALL INTESTINE

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LARGE INTESTINE

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LIVER

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GALL BLADDER AND BILE DUCT

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PANCREAS, SPLEEN, KIDNEYS

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GREAT VESSELS AND DIAPHRAGM

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NERVE PLEXUSES

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MALE PELVIS

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FEMALE PELVIS

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PELVIC JOINTS AND WALLS

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PERINEUM

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PART 2: LOWER LIMB LAQs (32 Questions)

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BONES AND JOINTS

• Head of femur (2/3 of sphere; covered with hyaline cartilage except fovea capitis where ligamentum teres attaches)
• Acetabulum of hip bone (lunate surface covered with cartilage; acetabular fossa filled with fat + ligamentum teres)
• Deepened by fibrocartilaginous acetabular labrum

• Proximally: Attached to rim of acetabulum + transverse acetabular ligament
• Distally: Anteriorly = intertrochanteric line (so anterior neck is intracapsular); Posteriorly = medial 2/3 of femoral neck (so posterior neck partly extracapsular)
• Iliofemoral ligament (Y-ligament of Bigelow) - anterosuperior; strongest ligament in body; prevents hyperextension
• Pubofemoral ligament - inferior; prevents excessive abduction
• Ischiofemoral ligament - posterior; prevents medial rotation and hyperextension
• Zona orbicularis - circular fibers forming collar around neck

1. Retinacular arteries (from medial and lateral circumflex femoral arteries) - run up neck under retinaculum - MOST IMPORTANT in adults; disrupted in intracapsular fractures → avascular necrosis
2. Artery in ligamentum teres (from obturator/medial circumflex femoral) - important in children; minimal in adults
3. Nutrient artery to shaft - does NOT reach head in adults

• Femoral nerve (anteriorly)
• Obturator nerve (inferiorly) - explains referred pain to knee in hip disease
• Sciatic nerve (posteriorly)
• Nerve to rectus femoris
• Superior gluteal nerve

• Anterior: Femoral artery (femoral triangle), femoral nerve
• Superior: Reflected head of rectus femoris
• Posterior: Sciatic nerve (posterior to joint at distance)
• Inferior: Obturator externus

1. Fracture neck of femur - intracapsular (Garden classification I-IV) → AVN; extracapsular (intertrochanteric) → less AVN risk; treated by hemiarthroplasty or DHS
2. Posterior dislocation - common in RTA (dashboard injury); sciatic nerve injury; head in obturator foramen or posterior to acetabulum
3. Anterior dislocation - rare; head in pubic or obturator position
4. Osteoarthritis - most common joint disease; superior joint space narrowing; THR
5. Congenital dislocation of hip (CDH) - Barlow + Ortolani tests
6. Trendelenburg sign - superior gluteal nerve / gluteus medius injury

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• Medial and lateral condyles of femur
• Medial and lateral tibial plateaus (tibial condyles) - with fibrocartilaginous menisci
• Posterior surface of patella (in trochlear groove of femur)

• Patellar ligament - from patella to tibial tuberosity
• Medial collateral ligament (MCL/tibial collateral ligament) - from medial femoral condyle to tibia; attached to medial meniscus
• Lateral collateral ligament (LCL/fibular collateral ligament) - from lateral femoral condyle to head of fibula; round cord; NOT attached to lateral meniscus
• Oblique popliteal ligament, arcuate popliteal ligament (posteriorly)

• Anterior cruciate ligament (ACL) - from anterior intercondylar area of tibia → lateral femoral condyle (posterior part); prevents anterior displacement of tibia; taut in extension
• Posterior cruciate ligament (PCL) - from posterior intercondylar area of tibia → medial femoral condyle (anterior part); prevents posterior displacement of tibia; stronger than ACL; taut in flexion

• Suprapatellar bursa (communicates with joint cavity - most important)
• Prepatellar bursa (housemaid's knee)
• Infrapatellar bursa - superficial and deep
• Semimembranosus bursa (posterior; can become Baker's cyst)
• Pes anserinus bursa

• Locking (last 30° of extension): Medial rotation of femur on fixed tibia (or lateral rotation of tibia on fixed femur); tightens all ligaments; makes joint a rigid pillar for standing; caused by quadriceps + gravity
• Unlocking: Popliteus muscle rotates femur laterally on tibia (or rotates tibia medially); "key that unlocks the knee"

• Genicular anastomosis: From popliteal artery (superior medial/lateral, inferior medial/lateral, middle genicular), femoral artery (descending genicular), anterior tibial recurrent artery

• Femoral nerve (via saphenous and nerve to vastus medialis)
• Obturator nerve (posterior division articular branch)
• Common peroneal nerve
• Tibial nerve

1. ACL tear - anterior drawer test positive, Lachman test; pivot shift; hemarthrosis
2. Meniscal tear - McMurray's test; medial more common; locked knee; arthroscopic meniscectomy
3. Unhappy triad (O'Donoghue) - ACL + MCL + medial meniscus (valgus force + rotation)
4. PCL tear - posterior drawer test positive
5. Patellar dislocation - lateral; predisposed by high Q angle, genu valgum
6. Baker's cyst - semimembranosus bursa enlargement
7. Knee aspiration - suprapatellar bursa (with knee extended, lateral or medial approach)
8. Osteoarthritis - medial compartment most commonly affected

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• Weak anteriorly and posteriorly
• Strengthened on sides by strong collateral ligaments

• Anterior talofibular (most commonly injured)
• Calcaneofibular
• Posterior talofibular (strongest of three)

• Dorsiflexion (extension): 20° - tibialis anterior, extensor hallucis, extensor digitorum, peroneus tertius
• Plantarflexion (flexion): 50° - gastrocnemius + soleus (main), tibialis posterior, flexor hallucis, flexor digitorum, peronei
• Note: True inversion/eversion occurs at subtalar (talocalcaneal) joint, NOT ankle joint

• Anterior: Extensor tendons, dorsalis pedis artery, deep peroneal nerve
• Posterior: Achilles tendon, flexor tendons, posterior tibial artery, tibial nerve
• Medial: Tendons beneath flexor retinaculum (Tom, Dick And Very Nervous Harry)
• Lateral: Peroneal tendons under peroneal retinacula

1. Lateral ankle sprain - most common sports injury; anterior talofibular ligament torn first (inversion injury)
2. Pott's fracture - eversion injury; deltoid ligament stronger than bone → avulses medial malleolus + fractures fibula
3. Trimalleolar fracture - medial + lateral + posterior malleolus
4. Achilles tendon rupture - Thompson's test positive
5. Tibiotalar fusion (arthrodesis) - for severe OA; sacrifices all ankle movement but relieves pain

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• Talocalcaneal joint (posterior facet - main weight-bearing subtalar joint)
• Talocalcaneonavicular joint (anterior)
• Interosseous talocalcaneal ligament in tarsal sinus (very strong - holds subtalar complex)
• Sustained by: Lateral collateral ligaments, cervical ligament, interosseous ligament

• Muscles: Tibialis anterior + posterior (main), flexor hallucis longus, flexor digitorum longus

• Muscles: Peroneus longus + brevis (main), extensor digitorum longus, peroneus tertius

1. Flat foot (pes planus) - loss of medial longitudinal arch; subtalar valgus; caused by weakness of tibialis posterior (main dynamic support of medial arch)
2. Club foot (talipes equinovarus) - equinus (plantarflexion) + varus (inversion) + adduction; idiopathic; treated by Ponseti method (serial casting)
3. Subtalar arthritis - after calcaneal fractures
4. Tarsal coalition - bony/fibrous fusion of tarsal bones; rigid flat foot

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• Components: Calcaneus, talus, navicular, 3 cuneiform bones, medial 3 metatarsals (1st, 2nd, 3rd)
• Keystone: Head of talus
• Highest arch; most important clinically

• Components: Calcaneus, cuboid, lateral 2 metatarsals (4th, 5th)
• Low arch; almost flat

• Bases of metatarsals + tarsus in coronal plane
• Keystone: 2nd metatarsal

• Shape of bones (talus perched on calcaneus)
• Plantar calcaneonavicular (spring) ligament - main static support of head of talus; bears most weight

• Tibialis posterior - inserts into navicular; inverts foot; main dynamic support
• Flexor hallucis longus - acts like a bowstring
• Flexor digitorum longus
• Peroneus longus (crosses from lateral to medial, supports transverse arch)
• Intrinsic foot muscles (short)
• Plantar fascia (plantar aponeurosis) - passive bowstring; windlass mechanism

1. Flat foot (pes planus) - failure of MLA; caused by tibialis posterior dysfunction; presents with medial ankle pain and "too many toes" sign
2. Pes cavus - exaggerated MLA; associated with neurological conditions (Charcot-Marie-Tooth, Friedreich's ataxia)
3. Plantar fasciitis - inflammation of plantar aponeurosis at calcaneal attachment; "first-step pain"
4. Hallux valgus - associated with loss of transverse arch; medial deviation of 1st MT + lateral deviation of big toe
5. March fracture - stress fracture of 2nd/3rd metatarsal shaft due to repeated stress

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GLUTEAL REGION

• Posterior gluteal line and area above it on ilium
• Posterior surface of sacrum and coccyx
• Sacrotuberous ligament

• Upper 3/4 → iliotibial tract (of fascia lata) → lateral tibial condyle
• Lower 1/4 → gluteal tuberosity of femur

• Powerful extensor of hip (from flexed position - climbing stairs, rising from chair)
• Lateral rotator of hip
• Upper fibers - abduct; lower fibers - adduct
• Through iliotibial tract - extends knee (stabilizes knee in extension)
• Antagonizes hip flexion

1. Intramuscular injection - upper outer quadrant of buttock to avoid sciatic nerve (which runs in lower medial quadrant) and inferior gluteal nerve 4 quadrants: Upper outer (safe), upper inner, lower outer, lower inner (dangerous)
2. Gluteal gait (extensor lurch) - inferior gluteal nerve palsy; trunk swings backward at heel strike
3. Used in gluteus maximus flap for pressure sore reconstruction
4. Weakened in hip OA and post-THR approaches

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• Exits through greater sciatic foramen
• Divides foramen into:
  • Above piriformis: Superior gluteal nerve (L4,5,S1) + superior gluteal vessels
  • Below piriformis: Sciatic nerve, inferior gluteal nerve (L5,S1,S2), pudendal nerve (S2,3,4), nerve to obturator internus, nerve to quadratus femoris, posterior cutaneous nerve of thigh, inferior gluteal vessels, internal pudendal vessels

1. Piriformis syndrome - sciatic nerve compression by tight piriformis; deep buttock pain radiating to leg; worsened by hip flexion/internal rotation; Pace test positive
2. Intrapelvic rupture of obturator internus - can compress pudendal nerve in Alcock's canal
3. Posterior hip dislocation injures sciatic nerve (which is close behind hip joint)

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• Origin: Outer surface of ilium between anterior and posterior gluteal lines
• Insertion: Lateral surface of greater trochanter
• Nerve: Superior gluteal nerve (L4, L5, S1)

• Origin: Outer surface of ilium between anterior and inferior gluteal lines
• Insertion: Anterior surface of greater trochanter
• Nerve: Superior gluteal nerve (L4, L5, S1)

• Abduction of hip (main abductors)
• Anterior fibers → medial rotation
• Posterior fibers → lateral rotation

• During single-leg stance (weight-bearing), gluteus medius and minimus contract on weight-bearing side → prevent opposite (swing) side pelvis from dropping

• When tested: Stand on one leg (affected side)
• Positive sign: Opposite (non-weight-bearing) side of pelvis drops
• Causes: Paralysis of gluteus medius/minimus (superior gluteal nerve palsy), fracture neck of femur, CDH, coxa vara
• Trendelenburg gait (gluteal/abductor gait): Trunk lurches TOWARD the affected side to keep center of gravity over weight-bearing foot (compensatory mechanism)

1. Superior gluteal nerve injury - in posterior approach to hip, faulty intramuscular injection
2. High lesion of superior gluteal nerve (above piriformis level) → bilateral trunk sway if walking (waddling gait if bilateral)

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THIGH

• Extension of knee (main extensors) - all 4 heads
• Rectus femoris also flexes hip (two-joint muscle)
• Vastus medialis - last 15° of extension + prevents lateral patellar dislocation

1. Quadriceps wasting - rapid in knee joint disease; loss of definition of vastus medialis first visible sign
2. Q angle (quadriceps angle) - between ASIS-patella and patella-tibial tuberosity lines; normal = 10-15° men, 15-20° women; increased → lateral patellar dislocation
3. Rectus femoris strain - common in kicking sports
4. Patella fracture - from sudden violent quadriceps contraction or direct trauma
5. Femoral nerve palsy - loss of knee extension; inability to climb stairs; absent patellar reflex

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• Adduction of hip (all)
• Gracilis - also flexes knee, medially rotates tibia
• Adductor magnus (ischial part) - extends hip

• Contents: Femoral artery, femoral vein, nerve to vastus medialis, saphenous nerve; at lower end → subsartorial plexus
• Covered by sartorius anteriorly

1. Obturator nerve lesion → weak adduction, sensory loss medial thigh
2. Gracilis used as free muscle flap, or for dynamic graciloplasty (reconstruction of anal sphincter)
3. Adductor longus strain ("groin strain") - common in football
4. Rider's bone (myositis ossificans) - in adductors of horse riders
5. Obturator hernia - protrudes through obturator canal; compresses obturator nerve; Howship-Romberg sign

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• Flexion of knee (main)
• Extension of hip (semitendinosus, semimembranosus, long head of biceps)
• When knee is flexed: Biceps femoris = lateral rotation of tibia; Semitendinosus + semimembranosus = medial rotation
• Hamstrings are two-joint muscles

1. Hamstring strain - common in sprinters; proximal musculotendinous junction
2. Hamstring tightness - limits SLR; contributes to low back pain
3. Hamstring graft used for ACL reconstruction (4-strand gracilis + semitendinosus graft)
4. Semitendinosus used in graciloplasty
5. Avulsion of ischial tuberosity - in adolescents with open apophysis

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• Base (superiorly): Inguinal ligament
• Medial border: Medial border of adductor longus
• Lateral border: Medial border of sartorius

• Femoral nerve (most lateral; outside femoral sheath)
• Femoral artery (central; within femoral sheath)
• Femoral vein (medial to artery; within femoral sheath)
• Femoral canal (most medial; contains lymph nodes + loose areolar tissue)
• Femoral branch of genitofemoral nerve
• Lateral cutaneous nerve of thigh (lateral, outside triangle proper - passes below inguinal ligament)
• Saphenous nerve (branch of femoral; within triangle)
• Deep inguinal lymph nodes

1. Femoral artery pulse - palpated at midinguinal point (midway between ASIS and symphysis pubis); NOT midpoint of inguinal ligament
2. Femoral artery cannulation - for angiography, cardiac catheterization, IABP
3. Femoral hernia - enters femoral ring → femoral canal → presents as a swelling below inguinal ligament; medial to femoral vein
4. Femoral vein thrombosis and DVT
5. Femoral nerve block - regional anesthesia for anterior thigh and knee surgery

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• Anterior/Roof: Sartorius (with subsartorial fascia)
• Anteromedial: Vastoadductor fascia (between vastus medialis and adductor longus/magnus)
• Lateral: Vastus medialis
• Posterior: Adductor longus (upper) and adductor magnus (lower)

1. Femoral artery (becomes popliteal artery as it passes through adductor hiatus)
2. Femoral vein (posterior to artery initially, then lateral)
3. Saphenous nerve (emerges through roof piercing subsartorial fascia)
4. Nerve to vastus medialis (on lateral wall)
5. Descending genicular artery (leaves through roof)

1. Femoral artery occlusion (atherosclerosis) - most common site is adductor canal → intermittent claudication of calf
2. Femoral artery aneurysm may develop at adductor hiatus
3. Hunter's canal block - regional anesthesia (saphenous nerve block) for medial leg and foot surgery
4. Perioperative femoral artery exposure - through sartorius to access vessel

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• Superolateral: Biceps femoris
• Superomedial: Semitendinosus + semimembranosus
• Inferolateral: Lateral head of gastrocnemius + plantaris
• Inferomedial: Medial head of gastrocnemius

1. Popliteal surface of femur
2. Posterior capsule of knee joint
3. Popliteus muscle

• Common peroneal nerve (most lateral + superficial; runs along medial border of biceps)
• Tibial nerve (central; deepest of neurovascular structures)
• Popliteal vein (between artery and nerve)
• Popliteal artery (deepest; directly on bone - vulnerable in supracondylar fracture)
• Popliteal lymph nodes (4-5; drain knee + deep leg)
• Genicular arteries (from popliteal)
• Short saphenous vein (drains into popliteal vein after piercing roof)

1. Popliteal artery is most vulnerable artery in supracondylar fracture of femur (tethered; distal fragment pulls artery)
2. Popliteal artery aneurysm - most common peripheral aneurysm; risk of distal embolism + limb ischemia
3. Baker's cyst (popliteal cyst) - posterior herniation of knee joint synovial membrane; through gap between medial gastrocnemius and semimembranosus; presents as painless swelling in popliteal fossa; associated with knee OA/RA
4. Popliteal pulse - difficult to feel; patient prone/supine with knee flexed; palpated deep
5. Common peroneal nerve - easily injured at lateral border of fossa (biceps femoris); leads to foot drop

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MUSCLES OF LEG

1. Foot drop - paralysis of anterior compartment (common peroneal nerve lesion at neck of fibula) → inability to dorsiflex → steppage gait
2. Anterior compartment syndrome - after tibial fracture; raised intracompartmental pressure → ischemia; 6 Ps; emergency fasciotomy
3. Tibialis anterior rupture - in elderly; foot drop
4. Deep peroneal nerve entrapment (anterior tarsal tunnel) - causes numbness 1st web space

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1. Achilles tendon rupture - Thompson's test positive (no plantarflexion on calf squeeze); most common in middle-aged; treated surgically
2. Achilles tendinitis - chronic overuse
3. Deep vein thrombosis - popliteal and posterior tibial veins
4. Tibialis posterior dysfunction → adult-acquired flat foot
5. Compartment syndrome (deep posterior) - fasciotomy required

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• Superior peroneal retinaculum - above lateral malleolus
• Inferior peroneal retinaculum - below lateral malleolus
• Contain tendons of peroneus longus and brevis

1. Peroneal tendon subluxation - superior retinaculum torn; tendons slip forward over lateral malleolus
2. Peroneus brevis avulsion - at 5th metatarsal base (inversion injury - mimics ankle sprain; "Jones fracture" = more proximal)
3. Superficial peroneal nerve injury - loss of eversion + sensory loss dorsum of foot (not 1st web space)
4. Compartment syndrome of lateral compartment - less common but possible

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• Runs between tibia and fibula, just above ankle
• Contains (in one compartment): All 4 extensor tendons pass under it

• Stem attached laterally to calcaneus; splits into upper and lower bands attached to medial malleolus and plantar fascia
• Compartments (lateral to medial):
  1. Extensor digitorum longus + peroneus tertius
  2. Extensor hallucis longus
  3. Tibialis anterior (most medial)
  4. Dorsalis pedis artery + deep peroneal nerve (between EHL and EDL)

• Between medial malleolus and calcaneus + medial surface of calcaneus
• Roof of tarsal tunnel
• Structures passing under (medial to lateral mnemonic - "Tom, Dick AND Very Nervous Harry"):
  1. Tibialis posterior
  2. Digitorum flexor longus
  3. And (posterior tibial Artery + 2 venae comitantes)
  4. Nerve - posterior tibial nerve (divides into medial and lateral plantar nerves)
  5. V - posterior tibial Vein (venae comitantes)
  6. Hallucis flexor longus (most posterior/inferior)

1. Tarsal tunnel syndrome - posterior tibial nerve compressed under flexor retinaculum → numbness/tingling sole of foot; treated by retinaculum release
2. Tendon tenosynovitis in retinacula - overuse; treated by rest/steroid injection

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NERVES OF LOWER LIMB

1. Formed within substance of psoas major (posterior divisions of L2,3,4)
2. Emerges from lateral border of psoas
3. Runs down in groove between psoas and iliacus (within iliacus fascia)
4. Passes under inguinal ligament (in muscular lacuna, lateral to femoral artery)
5. Immediately divides into multiple branches in femoral triangle

• Muscular: Iliacus (in abdomen), sartorius, pectineus, and 4 heads of quadriceps
• Cutaneous (anterior): Medial and intermediate cutaneous nerves of thigh (anterior thigh sensation)
• Saphenous nerve (longest branch): Passes into adductor canal; pierces roof; descends along medial leg to medial malleolus and medial side of foot (sensory)
• Articular: To hip and knee joints

1. Femoral nerve block - below inguinal ligament, lateral to femoral artery; provides analgesia for femur fracture, knee surgery; 3-in-1 block (femoral + lateral cutaneous nerve + obturator nerve)
2. Femoral nerve injury - in psoas hematoma (hemophilia, anticoagulants), retractor injury during abdominal surgery, hip arthroplasty; presents: weakness of knee extension + loss of patellar reflex + sensory loss anterior thigh + medial leg
3. Femoral nerve stretch test - extension of hip stretches nerve; positive in L2/3/4 pathology (anterior disc prolapse, psoas abscess)
4. Saphenous nerve injury during great saphenous vein harvesting → numbness medial leg

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1. Emerges from medial border of psoas (at pelvic brim)
2. Crosses pelvic brim (lateral to ureter and ovary)
3. Runs along lateral pelvic wall in obturator canal (in obturator foramen)
4. Divides into anterior and posterior divisions in obturator foramen

• Anterior division: Adductor longus, adductor brevis, gracilis; cutaneous to medial thigh; to hip joint
• Posterior division: Obturator externus, adductor magnus (part); articular branch to knee joint

1. Obturator nerve injury - in pelvic fracture, obturator hernia, gynecological surgery; weakness of adductors, sensory loss medial thigh
2. Howship-Romberg sign - pain along medial thigh to knee (articular branch) in obturator hernia; increased by hip extension, abduction, medial rotation; decreased by flexion
3. Articular branch to knee - explains referred pain to medial knee in hip joint disease (Hilton's law)
4. Adductor spasm in cerebral palsy - scissor gait; obturator nerve block/neurectomy

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1. Exits pelvis through greater sciatic foramen below piriformis
2. Passes midway between greater trochanter and ischial tuberosity
3. Descends deep to gluteus maximus
4. Enters back of thigh; deep to long head of biceps femoris
5. At apex of popliteal fossa, divides into tibial nerve (medial) and common peroneal nerve (lateral)

• Division may occur higher up (sometimes in pelvis)

• Above: Superior gluteal vessels (above piriformis)
• Below: Inferior gluteal vessels, pudendal nerve, nerve to obturator internus, posterior cutaneous nerve of thigh
• Medial: Ischial tuberosity
• Lateral: Greater trochanter

• Nerve to biceps femoris long head, semimembranosus, semitendinosus (tibial component)
• Nerve to biceps femoris short head (common peroneal component)
• Articular branch to hip (inconstant)

• Continues through popliteal fossa, passes under soleal arch, along posterior compartment of leg
• Supplies: All posterior compartment of leg + plantar muscles of foot
• Sensory: Sole of foot, heel, plantar surface of toes

• Winds around neck of fibula → divides into deep and superficial peroneal nerves
• Supplies: Anterior and lateral compartments of leg
• Sensory: Dorsum of foot, lateral leg

1. Sciatic nerve injury in posterior hip dislocation - damage to foot dorsiflexion + plantar flexion; sensory below knee
2. Misplaced gluteal injection - into lower medial quadrant; avoid by upper outer quadrant
3. Sciatica - compression of L4/5 or L5/S1 nerve roots by disc prolapse; pain radiating down posterior thigh → leg → foot; SLR test positive; Lasègue sign
4. Piriformis syndrome - sciatic compression by piriformis; deep buttock pain
5. Common peroneal nerve injury at neck of fibula - foot drop + sensory loss dorsum of foot + lateral leg

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1. Runs along medial border of biceps femoris tendon (lateral wall of popliteal fossa)
2. Winds around neck of fibula (superficial; under deep fascia and head of peroneus longus)
3. Divides into deep and superficial peroneal nerves just below neck of fibula

• Lateral cutaneous nerve of calf (sensory to upper lateral leg)
• Sural communicating branch (contributes to sural nerve)
• Articular branches to knee

• Runs in lateral compartment; supplies peroneus longus + brevis
• Emerges through deep fascia in lower 1/3 of leg; sensory to dorsum of foot (except 1st web space)

• Runs in anterior compartment with anterior tibial artery
• Supplies all muscles of anterior compartment (tibialis anterior, EHL, EDL, peroneus tertius)
• Terminal: Sensory to 1st web space (dorsal + plantar aspects)
• Continues as dorsalis pedis nerve

1. Commonest site of injury: Neck of fibula
   • Causes: Crossing legs, below-knee plaster, direct blow, pressure from cast, knee arthroplasty
2. Foot drop - loss of dorsiflexion and eversion; high steppage gait; inability to walk on heels
3. Sensory loss: Dorsum of foot (superficial) + 1st web space (deep)
4. Ankle jerk (S1) preserved (tibial nerve)
5. Treatment: AFOS (ankle-foot orthosis), nerve decompression or repair

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1. Passes vertically through popliteal fossa (most superficial of neurovascular structures)
2. Passes under soleal arch (fibrous arch of soleus)
3. Descends in deep posterior compartment of leg (between flexor digitorum longus and flexor hallucis longus)
4. Passes behind medial malleolus under flexor retinaculum
5. Divides into medial and lateral plantar nerves

• Popliteal fossa: Articular branches (to knee), muscular (gastrocnemius, soleus, plantaris, popliteus), sural nerve (sensory - lateral side of leg + foot)
• Leg: To all deep posterior compartment muscles (tibialis posterior, FDL, FHL)
• Calcaneal branches: Sensory to heel
• Medial plantar nerve (L4,L5): Main sensory nerve to sole; supplies medial 3½ toes (plantar surface); muscles: abductor hallucis, flexor digitorum brevis, flexor hallucis brevis, 1st lumbrical; analogue of median nerve in hand
• Lateral plantar nerve (S1,S2): Lateral 1½ toes and remaining intrinsic muscles; analogue of ulnar nerve in hand

1. Tarsal tunnel syndrome - tibial nerve compressed under flexor retinaculum; burning pain + numbness in sole of foot; positive Tinel's at medial malleolus; treated by retinaculum release
2. High tibial nerve injury (popliteal fossa) - loss of plantarflexion + all intrinsic foot muscles + sensation of sole; calcaneal gait
3. Sural nerve: Formed by sural communicating branch (from common peroneal) + medial sural cutaneous nerve (from tibial); courses with small saphenous vein; commonly used as nerve graft donor

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1. Lumbosacral trunk compression - in obstructed labor → foot drop
2. Pelvic fracture - injury to multiple sacral plexus components
3. Cauda equina syndrome - compression of lumbar and sacral roots in spinal canal → bilateral leg weakness, saddle anesthesia, sphincter dysfunction

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BLOOD VESSELS

1. Enters femoral triangle (common femoral artery - between inguinal ligament and profunda femoris origin)
2. Branches: Superficial femoral artery continues; profunda femoris arises posterolaterally
3. Traverses femoral triangle
4. Enters adductor (Hunter's) canal
5. Passes through adductor hiatus in adductor magnus at junction of middle and lower thirds of thigh
6. Continues as popliteal artery

• Superficial epigastric, superficial circumflex iliac, superficial external pudendal arteries (in femoral triangle)
• Profunda femoris (deep femoral artery) - from lateral side; gives medial and lateral circumflex femoral arteries + 3 perforating arteries
• Medial circumflex femoral artery - main blood supply to head of femur via retinacular vessels
• Descending genicular artery (near adductor hiatus)

1. Femoral pulse - at midinguinal point; most accessible large pulse in body
2. Femoral artery cannulation - for coronary angiography, IABP, arterial line
3. Femoral artery injury - in femoral fractures; can cause massive hemorrhage
4. Leriche syndrome - aortoiliac occlusion; absent femoral pulses bilaterally + buttock claudication + impotence
5. Profunda femoris - main collateral when SFA occluded; "lifeboat" of the limb

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1. Enters popliteal fossa through adductor hiatus
2. Most deeply placed structure in popliteal fossa (directly on bone)
3. Courses slightly laterally as it descends
4. At lower border of popliteus muscle, divides into anterior and posterior tibial arteries

• Superior medial + lateral genicular arteries
• Middle genicular artery (to cruciate ligaments)
• Inferior medial + lateral genicular arteries
• Muscular branches to hamstrings + gastrocnemius

1. Most vulnerable artery in supracondylar fracture - posterior fragment displaces posteriorly and is held by gastrocnemius; artery tethered to bone → injury; check for distal pulses
2. Popliteal aneurysm - most common peripheral aneurysm; bilateral in 50%; risk of thrombosis + distal embolization → limb ischemia; presents as pulsatile popliteal mass
3. Anterior knee dislocation - stretches/tears popliteal artery
4. Popliteal pulse palpation - patient prone with knee flexed 30-45°; deep digital pressure in fossa

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• Inferior gluteal artery (from internal iliac)
• Ascending branch of medial circumflex femoral
• Transverse branch of lateral circumflex femoral
• First perforating artery (from profunda femoris)
• These form a + shape on posterior thigh

• Descending genicular (from femoral)
• Superior medial + lateral genicular (from popliteal)
• Inferior medial + lateral genicular (from popliteal)
• Middle genicular (from popliteal)
• Anterior + posterior tibial recurrent arteries

• Hip anastomosis: After gradual occlusion of femoral/iliac arteries, collateral circulation may develop; BUT NOT sufficient in acute trauma/occlusion
• Knee anastomosis: After popliteal occlusion, these can maintain distal limb (but collateral inadequate in sudden occlusion)

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• Longest vein in body
• Origin: From dorsal venous arch of foot at medial end
• Course: Anterior to medial malleolus → along medial leg → behind medial knee → medial thigh → passes through saphenous opening in fascia lata → drains into femoral vein 3-4 cm below inguinal ligament (saphenofemoral junction)
• Tributaries: Superficial epigastric, superficial circumflex iliac, superficial external pudendal veins (at SFJ)
• Perforating veins (Cockett's perforators in lower leg; Dodd's/Boyd's perforators in thigh)

• Origin: Dorsal venous arch at lateral end
• Course: Behind lateral malleolus → up back of leg → pierces popliteal fascia → joins popliteal vein (at saphenopopliteal junction)

1. Great saphenous vein harvest - used in coronary artery bypass graft (CABG) and peripheral vascular bypass
2. Varicose veins - incompetence of saphenofemoral junction and perforating veins; blood refluxes into superficial veins; tortuous dilated veins on medial leg; Trendelenburg test; EVLA/foam sclerotherapy/surgery
3. DVT - immobility, long flights, post-surgery; virchow's triad: stasis + hypercoagulability + endothelial injury; Homans' sign (unreliable); diagnosis by Doppler USS; treatment: LMWH/DOAC
4. Varicose ulcer - medial gaiter area (Cockett's perforators); treatment: compression bandaging
5. Long saphenous vein grafts tend to develop intimal hyperplasia over time

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• Follow great saphenous vein → superficial inguinal lymph nodes (SILN)
• Follow small saphenous vein → popliteal lymph nodes → deep inguinal nodes

• Follow deep blood vessels → popliteal nodes → deep inguinal nodes (medial to femoral vein in femoral canal - Cloquet's node)

• Horizontal group (along inguinal ligament): Drain scrotum/labia, perineum, vulva, lower anal canal, umbilical region, lower abdominal wall, buttock
• Vertical group (along great saphenous vein): Drain entire superficial lower limb

• Cloquet's (Rosenmüller's) node - highest deep node; in femoral canal
• Drain deep leg + glans penis/clitoris + deep perineum

• Testis/ovary → para-aortic nodes (NOT inguinal)
• Anal canal above pectinate line → internal iliac nodes
• Anal canal below pectinate line → superficial inguinal nodes
• Dorsal glans penis → deep inguinal nodes

1. Lymphedema - primary (Milroy's disease) or secondary (post-surgery, filariasis); treated by compression stockings, lymphatic drainage massage
2. Inguinal lymphadenopathy - reactive (infections of lower limb, perineum), metastatic (melanoma, squamous cell from lower limb/perineum/anal canal/vulva/scrotum)
3. Filariasis - Wuchereria bancrofti; lymphatic obstruction; massive elephantiasis

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FASCIA AND COMPARTMENTS

• Raised intracompartmental pressure → ischemia → irreversible damage if untreated

1. Pain (out of proportion, worst with passive stretch)
2. Pressure (tense swelling)
3. Paresthesia (nerve ischemia)
4. Paralysis (muscle ischemia)
5. Pallor
6. Pulselessness (late sign)

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• Deep fascia of the thigh; thick and strong
• Complete tubular sheath enclosing all thigh muscles
• Thickened laterally as the iliotibial tract (band)
• Attached below to patella, tibial condyles, head of fibula

• Thickening of fascia lata on lateral side
• From iliac crest (and anterior superior iliac spine)
• Tensor fascia lata (from ASIS) and gluteus maximus (upper fibers) both insert into it
• Inserts below into Gerdy's tubercle (anterolateral tibial condyle) + patella

• Lateral stabilizer of knee (prevents excessive varus)
• In extension: Lies anterior to lateral femoral epicondyle - assists extension
• In flexion (>30°): Slides posterior to lateral femoral epicondyle - assists flexion

1. Iliotibial band syndrome (ITBS) - friction over lateral femoral epicondyle when knee repeatedly flexes/extends (runners, cyclists); lateral knee pain; Ober's test positive
2. ITB used as graft for lateral knee reconstruction
3. Fasciotomy for anterolateral compartment - through fascia lata
4. Saphenous opening (fossa ovalis) - oval defect in fascia lata where great saphenous vein drains into femoral vein; covered by cribriform fascia

• 45 LAQs - Abdomen & Pelvis (complete answers for all: inguinal canal, rectus sheath, inguinal ligament, abdominal wall layers, peritoneum, lesser sac, greater omentum, mesenteries, stomach, duodenum, jejunum/ileum, colon, appendix, liver, porta hepatis, portal vein, gallbladder, biliary apparatus, pancreas, spleen, kidneys, renal fascia, ureter, suprarenal glands, abdominal aorta, IVC, diaphragm, lumbar plexus, celiac plexus, male urethra, prostate, urinary bladder, uterus, broad ligament, round ligament, ovary, fallopian tube, pelvic floor, sacroiliac joint, pelvic walls, ischiorectal fossa, anal canal, male perineum, female perineum)
• 32 LAQs - Lower Limb (complete answers for all: hip joint, knee joint, ankle joint, subtalar joint, foot arches, gluteus maximus, short external rotators, gluteus medius/minimus, quadriceps, adductors, hamstrings, femoral triangle, adductor canal, popliteal fossa, anterior compartment, posterior compartment, lateral compartment, retinacula, femoral nerve, obturator nerve, sciatic nerve, common peroneal nerve, tibial nerve, lumbosacral plexus, sacral plexus, femoral artery, popliteal artery, arterial supply, venous drainage, lymphatic drainage, fascial compartments, fascia lata)