---

MBBS 1st Year Anatomy - Lower Limb Test Syllabus

Learning Objectives (Vishram Singh Style)

---

1. Hip Bone - Features and Attachments

• The hip (innominate) bone consists of three parts fused at the acetabulum: ilium (superior), ischium (posteroinferior), and pubis (anteroinferior). Fusion is complete by age 23 at the Y-shaped triradiate cartilage.

• Body forms the upper 2/5 of acetabulum; wing (ala) projects superiorly
• Key features: iliac crest (ASIS and AIIS anteriorly; PSIS and PIIS posteriorly), iliac fossa (origin of iliacus), gluteal surface (3 gluteal lines - posterior, anterior, inferior)
• Attachments: gluteus maximus (posterior gluteal line), gluteus medius (between posterior and anterior gluteal lines), gluteus minimus (between anterior and inferior gluteal lines), sartorius (ASIS), rectus femoris straight head (AIIS)

• Body + ramus form the ischiopubic ramus
• Key features: ischial tuberosity (hamstrings origin), ischial spine (sacrospinous ligament), greater and lesser sciatic notches
• Attachments: hamstrings (biceps femoris long head, semitendinosus, semimembranosus) from ischial tuberosity; adductor magnus (ischiopubic ramus + ischial tuberosity)

• Body, superior ramus, inferior ramus
• Key features: pubic crest, pubic tubercle (inguinal ligament attachment), pectineal line (pecten pubis), obturator foramen
• Attachments: inguinal ligament (pubic tubercle), adductor longus and gracilis (body), pectineus (pectineal line)

• Formed by ilium (upper 2/5), ischium (lower and posterior 2/5), pubis (anterior 1/5)
• Has lunate (articular) surface and non-articular acetabular fossa centrally
• Acetabular notch converted to foramen by transverse acetabular ligament
• Deepened by fibrocartilaginous acetabular labrum

---

2. Femur - Features and Attachments

• Head: spherical, articular surface covered by hyaline cartilage (except fovea capitis); fovea is attachment for ligamentum teres (ligament of head)
• Neck: cylindrical, connects head to shaft at ~125° angle (neck-shaft angle); projects anteromedially; antiversion angle ~15° anteriorly
• Greater trochanter: extends superiorly; lateral surface - gluteus medius (posterior part), gluteus minimus (anterior part); medial surface/trochanteric fossa - obturator externus; above fossa - obturator internus + gemelli; posterior margin - piriformis
• Lesser trochanter: posteromedial projection; attachment of iliopsoas (psoas major + iliacus)
• Intertrochanteric line (anterior): connects trochanters anteriorly; capsule of hip joint attaches here; iliofemoral ligament base
• Intertrochanteric crest (posterior): connects trochanters posteriorly; quadrate tubercle on it (quadratus femoris inserts here)

• Triangular in cross-section in middle
• Linea aspera (posterior rough ridge): medial lip - adductors longus/brevis/magnus, pectineus, vastus medialis; lateral lip - vastus lateralis, short head of biceps femoris, gluteus maximus (gluteal tuberosity)
• Pectineal line (spiral line): pectineus
• Gluteal tuberosity: part of gluteus maximus insertion

• Two condyles (medial and lateral), separated posteriorly by intercondylar fossa
• Medial condyle: adductor tubercle at top (adductor magnus hamstring part), medial epicondyle (tibial collateral ligament), origin of medial head of gastrocnemius
• Lateral condyle: lateral epicondyle (fibular collateral ligament), popliteal groove, origin of lateral head of gastrocnemius
• Patellar surface: V-shaped groove anteriorly for patella

---

3. Hip Joint - With Clinicals

• Head of femur (hyaline cartilage, except fovea)
• Lunate surface of acetabulum (broadest superiorly, covered by hyaline cartilage)
• Acetabular labrum deepens the socket; transverse acetabular ligament bridges the acetabular notch

• Fibrous membrane: proximally attached to rim of acetabulum and transverse acetabular ligament; distally attached to intertrochanteric line anteriorly, and midneck posteriorly
• The retinacular fibers (Weitbrecht's retinaculum) carry blood vessels to the femoral neck/head

• Iliofemoral ligament (Y-ligament of Bigelow): strongest; apex at AIIS + acetabular rim, base at intertrochanteric line; Y-shaped; prevents hyperextension
• Pubofemoral ligament: base at iliopubic eminence; blends with iliofemoral ligament; limits abduction and extension
• Ischiofemoral ligament: posterior; ischium to greater trochanter; limits medial rotation and extension

• Ligamentum teres (ligament of head of femur): from fovea capitis to acetabular fossa and transverse acetabular ligament; carries the acetabular branch of obturator artery

• Medial circumflex femoral artery (main supply, via retinacular branches - most important)
• Lateral circumflex femoral artery
• Obturator artery via ligamentum teres (minor)
• Nutrient artery of femur

• Fracture neck of femur: Common in elderly osteoporotic women. The medial circumflex femoral artery is damaged - causes avascular necrosis (AVN) of femoral head. Intracapsular fractures are particularly prone to AVN. Limb is shortened, externally rotated, and adducted.
• Congenital dislocation of hip (CDH / DDH): Failure of normal development of acetabulum or femoral head. Test: Ortolani's sign (click on abduction), Barlow's test. Galeazzi sign (limb shortening).
• Osteoarthritis of hip: Gradual wearing of hyaline cartilage; joint space narrows, osteophytes form, pain referred to groin and knee.
• Trendelenburg's test: Tests abductors (gluteus medius/minimus via superior gluteal nerve). If positive - pelvis tilts to unsupported side when standing on affected leg; seen in superior gluteal nerve palsy or hip dislocation.
• Dislocation of hip: Usually posterior (dashboard injury). Limb shortened, internally rotated, adducted. Risk of sciatic nerve injury.

---

4. Knee Joint - With Clinicals

1. Femorotibial (weight-bearing)
2. Femoropatellar (reduces tendon friction)

• Medial and lateral femoral condyles
• Corresponding tibial condyle plateaus (medial plateau is oval; lateral is more circular)
• Posterior surface of patella (V-shaped, articulates in patellar groove of femur)
• All covered by hyaline cartilage

• Fibrocartilaginous C-shaped structures between femoral and tibial condyles
• Medial meniscus: C-shaped, larger, attached to tibial collateral ligament and capsule (less mobile, more often torn)
• Lateral meniscus: more circular, NOT attached to fibular collateral ligament (more mobile, less often torn)
• Connected anteriorly by transverse ligament of knee
• Function: improve congruency, shock absorption, lubrication, proprioception

• Tibial (medial) collateral ligament: femoral medial epicondyle to medial tibial condyle + shaft; prevents valgus (abduction) stress; fused with medial meniscus
• Fibular (lateral) collateral ligament: lateral femoral epicondyle to head of fibula; cord-like; NOT fused with lateral meniscus; prevents varus (adduction) stress
• Anterior cruciate ligament (ACL): tibial intercondylar area (anterior) to posterior lateral wall of intercondylar fossa; prevents anterior displacement of tibia on femur; taut in extension
• Posterior cruciate ligament (PCL): tibial intercondylar area (posterior) to medial wall of intercondylar fossa; prevents posterior displacement of tibia; taut in flexion; stronger than ACL
• Patellar ligament: continuation of quadriceps tendon, patella to tibial tuberosity
• Oblique popliteal ligament: expansion of semimembranosus; strengthens posterior capsule
• Arcuate popliteal ligament: reinforces posterolateral capsule

• In full extension, lateral femoral condyle stops rotating while medial condyle continues → tibia rotates laterally on femur (or femur medially on tibia) → joint "locks"
• Unlocking: popliteus muscle medially rotates femur (laterally rotates tibia) to unlock the knee
• This reduces muscular effort needed to maintain standing

• Meniscal injuries: Medial meniscus torn more often (attached to capsule and tibial collateral ligament). Mechanism: flexion + rotation of knee. McMurray's test. "Locking" of knee. Treated by arthroscopic meniscectomy.
• ACL injury: Most common ligament injury. Mechanism: sudden pivot, cutting, hyperextension. Presents with pop, immediate swelling (hemarthrosis). Anterior drawer test (knee at 90°), Lachman's test (knee at 20-30° flexion - more sensitive). MRI confirms. Treatment: surgical reconstruction.
• PCL injury: Requires high force; "dashboard injury" (blow to flexed knee). Posterior drawer test, tibial sag sign. Less common.
• Unhappy triad (O'Donoghue's triad): ACL + medial meniscus + tibial collateral ligament injured together; due to valgus force + lateral rotation.
• Prepatellar bursitis (housemaid's knee): Repeated kneeling → inflamed prepatellar bursa.
• Infrapatellar bursitis (clergyman's knee): More distal swelling.
• Baker's cyst: Distension of semimembranosus bursa; communicates with joint in adults; palpable behind knee.
• Patellar tap sign: Tests for fluid in knee (effusion).
• Valgus/Varus stress tests: Test collateral ligaments.

---

5. Thigh - Anterior (Front) Compartment

• Quadriceps femoris = rectus femoris + three vasti. Inserts via quadriceps tendon to patella, then via patellar ligament to tibial tuberosity.
• Patellar reflex (L2-L4) tests femoral nerve integrity.
• Articularis genu: small muscle pulling suprapatellar bursa upward during extension.

---

6. Thigh - Medial Compartment

• Adductor hiatus: gap in adductor magnus between adductor and hamstring parts; femoral vessels pass through to become popliteal vessels.
• Pes anserinus: Common insertion of sartorius, gracilis, semitendinosus on medial tibia (mnemonic: SGT - "Say Grace before Tea")

---

7. Thigh - Posterior Compartment (Hamstrings)

• All 3 crossing the hip joint originate from ischial tuberosity - are "true hamstrings" (flexors of knee + extensors of hip)
• Short head of biceps femoris crosses only knee joint
• Sciatic nerve descends between them, under biceps femoris long head

---

8. Gluteal Region

1. Superior gluteal nerve (above piriformis)
2. Sciatic nerve (below piriformis)
3. Inferior gluteal nerve (below piriformis)
4. Posterior cutaneous nerve of thigh (below piriformis)
5. Nerve to quadratus femoris (below piriformis)
6. Nerve to obturator internus (below piriformis)
7. Pudendal nerve (below piriformis)

• Piriformis syndrome: Sciatic nerve compressed by piriformis; mimics disc prolapse; pain radiating down leg.
• Intramuscular injection site: Upper outer quadrant of gluteus maximus (to avoid sciatic nerve and superior gluteal vessels).
• Trendelenburg gait: Superior gluteal nerve damage → gluteus medius/minimus paralysis → pelvis drops to opposite side → compensatory lurching toward weak side.

---

9. Femoral Triangle

• Base (superior): Inguinal ligament
• Lateral border: Medial border of sartorius
• Medial border: Medial border of adductor longus
• Floor: Iliopsoas (laterally) + pectineus (medially) + adductor longus (medially)
• Roof: Fascia lata (with saphenous opening) + skin + superficial fascia

• N - Femoral Nerve (outside femoral sheath, most lateral)
• A - Femoral Artery (in femoral sheath)
• V - Femoral Vein (in femoral sheath)
• Y - Y-lymphatics/femoral canal (most medial, in femoral sheath)

• Funnel-shaped sleeve of fascia surrounding femoral artery, vein, and femoral canal
• Continues from transversalis fascia (anterior) and iliac fascia (posterior)
• 3 compartments: Lateral (femoral artery), middle (femoral vein), medial (femoral canal with lymphatics and lymph node of Cloquet)
• Femoral nerve is NOT inside the sheath
• Femoral canal = most medial, contains lymphatics; its superior opening = femoral ring (potential weak point for femoral hernia)

• Anterior: inguinal ligament
• Posterior: pectineal ligament (Cooper's ligament)
• Medial: lacunar ligament
• Lateral: femoral vein

• Femoral pulse: palpable just below inguinal ligament, midpoint between ASIS and pubic symphysis.
• Femoral hernia: Through femoral ring into femoral canal; more common in women; passes below and lateral to pubic tubercle (vs inguinal hernia which is above and medial); high risk of strangulation due to rigid ring.
• Femoral artery access: Used for coronary angiography, peripheral vascular procedures, cardiac catheterization.
• Femoral vein cannulation: For CVP monitoring, dialysis, Swan-Ganz catheter.

---

10. Adductor Canal (Hunter's Canal / Subsartorial Canal)

• Anterolateral: Vastus medialis
• Posterior: Adductor longus (proximally) and adductor magnus (distally)
• Medial/Roof: Sartorius + vastoadductor membrane (fibrous sheet between sartorius and adductor muscles)

1. Femoral artery
2. Femoral vein (posterior to artery)
3. Saphenous nerve (branch of femoral nerve - only nerve in canal)
4. Nerve to vastus medialis (passes through canal briefly)
5. Descending genicular artery (branches from femoral artery within canal)

• Adductor canal block (Hunter's canal block): Regional anaesthesia technique; blocks saphenous nerve; used for analgesia after knee surgery with less motor block than femoral nerve block.
• Femoral to popliteal bypass surgery: Surgeons use adductor canal as landmark for femoral/popliteal artery access.

---

11. Femoral Nerve

1. Descends in groove between psoas major and iliacus in abdomen
2. Gives branches to iliacus (in abdomen)
3. Passes under inguinal ligament (lateral half of gap) in the "muscular lacuna"
4. Enters femoral triangle lateral to femoral artery (outside femoral sheath)
5. Immediately divides into anterior and posterior divisions

• Branch to iliacus, pectineus

• Medial cutaneous nerve of thigh
• Intermediate cutaneous nerve of thigh
• Muscular branches to sartorius

• Muscular branches to quadriceps femoris (all four heads)
• Saphenous nerve - longest branch; accompanies femoral artery in adductor canal; exits via vastoadductor membrane; supplies medial leg, ankle, foot down to ball of great toe

• Anterior and medial thigh (medial + intermediate cutaneous nerves)
• Medial leg, ankle, foot (via saphenous nerve)

• Cause: Psoas abscess, femoral hernia surgery, hip surgery, retroperitoneal hematoma, diabetes (diabetic amyotrophy/femoral neuropathy), prolonged lithotomy position
• Features:
  • Weakness of hip flexion (iliopsoas also gets L1-L3 direct, but iliacus affected)
  • Quadriceps paralysis - inability to extend knee (most prominent feature)
  • Loss of knee jerk (L3, L4)
  • Wasting of quadriceps
  • Loss of sensation over anterior thigh and medial leg and foot (saphenous nerve territory)
• Meralgia paraesthetica: Not femoral nerve - it is lateral cutaneous nerve of thigh (L2, L3) compressed under inguinal ligament; tingling/numbness over lateral thigh.

---

12. Obturator Nerve

1. Descends medial to psoas muscle
2. Enters true pelvis, passes along lateral pelvic wall
3. Passes through obturator canal (obturator groove in obturator foramen)
4. Enters medial compartment of thigh
5. Immediately divides into anterior and posterior divisions - separated by adductor brevis

• Supplies: adductor longus, adductor brevis, gracilis, pectineus (occasional)
• Cutaneous branch: medial thigh skin

• Supplies: obturator externus, adductor brevis (occasional), adductor magnus (adductor part)
• Articular branch to posterior aspect of knee joint

• Cause: Obturator hernia, pelvic fracture, parturition (childbirth), obturator internus surgery, hip replacement surgery, large pelvic tumors
• Features:
  • Weakness of adduction of thigh (most prominent)
  • Weakness of medial rotation
  • Loss of small area of sensation over medial thigh
  • Howship-Romberg sign: Pain along inner thigh radiating to knee; seen in obturator hernia (nerve compressed at obturator canal); aggravated by thigh extension and medial rotation, relieved by flexion.
  • Trendelenburg's test stays negative (abductors not affected)
• Referred pain: Obturator nerve supplies hip and knee joints; hip pathology can present as knee pain in children (via obturator nerve). This is Hilton's Law in practice.

---

13. Trochanteric Anastomosis

1. Superior gluteal artery (branch of internal iliac)
2. Inferior gluteal artery (branch of internal iliac)
3. Medial circumflex femoral artery (branch of profunda femoris)
4. Lateral circumflex femoral artery (branch of profunda femoris)
5. Deep circumflex iliac artery (branch of external iliac) - some texts include

• Provides blood supply to the femoral head and neck via retinacular branches
• The medial circumflex femoral artery is the most important contributor to femoral head blood supply (through deep branch passing between obturator externus and adductor brevis, then over back of quadratus femoris to enter neck)
• Provides collateral pathway between internal iliac and profunda femoris circulation

---

14. Cruciate Anastomosis

1. Transverse branch of medial circumflex femoral artery (from profunda femoris)
2. Transverse branch of lateral circumflex femoral artery (from profunda femoris)
3. Inferior gluteal artery (from internal iliac, below piriformis)
4. First perforating branch of profunda femoris artery

• Provides collateral circulation between internal iliac (via inferior gluteal) and femoral/profunda femoris systems
• If the common femoral or external iliac artery is occluded, blood can reach the lower limb through this anastomosis
• Maintains perfusion to thigh muscles

---

Quick Revision Table - Key Nerve-Muscle-Action

---

Key Clinical Signs to Remember

---

---

• Bones (features, key landmarks, muscle attachments)
• Joint type, articular surfaces, capsule, ligaments, movements
• Compartment-wise muscles (origin, insertion, nerve, action)
• Nerve courses, branches, and muscles supplied
• Arterial anastomoses with constituent vessels
• Clinical correlates (injuries, tests, pathology) for every topic

1. Fracture neck of femur → AVN (medial circumflex femoral artery)
2. Trendelenburg test → superior gluteal nerve / abductor weakness
3. ACL injury - Lachman's test > Anterior drawer test
4. Unhappy triad - ACL + medial meniscus + tibial collateral ligament
5. Femoral hernia - through femoral ring, below and lateral to pubic tubercle
6. Obturator nerve palsy → adductor weakness + Howship-Romberg sign
7. Posterior hip dislocation → sciatic nerve injury
8. Medial meniscus torn more than lateral (attached to capsule)
9. Cruciate anastomosis at lesser trochanter level; trochanteric anastomosis at femoral neck level

• Gray's Anatomy for Students
• Netter's Atlas of Human Anatomy
• THIEME General Anatomy & Musculoskeletal System (Atlas)
• Color Atlas of Human Anatomy (Vols 1, 2, 3)
• Imaging Anatomy - Bones, Joints, Vessels and Nerves

1. Reframe the previous notes in Snell's style - Snell organizes content as: Gross anatomy → Relations → Blood supply → Nerve supply → Lymphatics → Clinical notes. I can rewrite each topic in that exact format using the data already retrieved from Gray's + THIEME.
2. Keep the same content but use Snell's clinical anatomy headings - Snell's clinical correlates (like "Clinical Notes" boxes) are very similar to what was covered; I can reformat with that structure.
3. Focus on specific topics - If you only want certain topics rewritten in Snell's format (e.g., just the joints, or just the nerves), I can do those in detail.

---

HIP JOINT

(Snell's Clinical Anatomy Format)

---

TYPE OF JOINT

---

ARTICULAR SURFACES

• Spherical, forming about two-thirds of a sphere
• Covered entirely by hyaline cartilage - except the fovea capitis (a small pit on its medial surface for attachment of the ligament of the head)

• Formed by ilium (upper 2/5), ischium (lower and posterior 2/5), pubis (anterior 1/5) - fused at the Y-shaped triradiate cartilage
• Only the lunate surface (horseshoe-shaped) is articular, covered by hyaline cartilage
• The acetabular fossa (central non-articular floor) contains a fat pad and loose connective tissue
• The acetabular labrum (fibrocartilaginous rim) deepens the socket and grips the femoral head - it converts a hemisphere into a more-than-hemisphere cup
• Inferiorly, the labrum bridges the acetabular notch as the transverse acetabular ligament, converting the notch into a foramen through which vessels enter the joint

---

FIBROUS CAPSULE

• To the rim of the acetabulum, base of the acetabular labrum, and the transverse acetabular ligament

• Anteriorly: along the entire intertrochanteric line (entire neck is intracapsular anteriorly)
• Posteriorly: along the neck of the femur, about 1 cm above the intertrochanteric crest (so the posterior part of the neck is extracapsular)

• Longitudinal fibers on the deep surface of the capsule that reflect upward along the femoral neck as retinacula
• These carry the retinacular blood vessels (branches of medial circumflex femoral artery) that supply the femoral head and neck - clinically very important

---

LIGAMENTS

A. Extracapsular Ligaments (reinforce the fibrous capsule)

• Strongest ligament in the body
• Triangular / Y-shaped
• Apex: anterior inferior iliac spine (AIIS) and rim of acetabulum
• Base: along the entire intertrochanteric line (upper and lower bands are thick; middle is thin - hence the Y appearance)
• Lies: anterior to the joint
• Function: Prevents hyperextension of the hip. In standing, body weight tends to push the trunk backward - iliofemoral ligament prevents this, reducing muscle work in upright posture

• Triangular
• Base (medial attachment): iliopubic eminence, superior pubic ramus, obturator membrane
• Apex (lateral attachment): blends with fibrous capsule and deep surface of iliofemoral ligament
• Lies: anteroinferior to the joint
• Function: Limits abduction and extension

• Spirally oriented
• Medial attachment: ischium, posteroinferior to acetabulum
• Lateral attachment: greater trochanter, deep to iliofemoral ligament
• Lies: posterior to the joint
• Function: Limits medial rotation and extension

B. Intracapsular Ligament

• Flat, triangular band inside the joint cavity
• Proximal (femoral) attachment: fovea capitis of the femoral head
• Distal (acetabular) attachment: acetabular fossa, transverse acetabular ligament, and margins of the acetabular notch
• Contents: carries the acetabular branch of the obturator artery - contributes to blood supply of femoral head (important in children; less so in adults)
• Function: Minor stabilizer; mainly a conduit for vessels. Becomes taut during adduction and lateral rotation.

---

SYNOVIAL MEMBRANE

• Attached to the margins of the articular surfaces of both bones
• Lines the entire fibrous capsule from inside
• Reflects back along the femoral neck (in the retinacula) to the margin of the femoral head cartilage
• Forms a tube-like sleeve around the ligamentum teres
• Covers the fat pad in the acetabular fossa

---

RELATIONS

---

BLOOD SUPPLY

• Superior and inferior gluteal arteries
• First perforating branch of profunda femoris

Clinical key: In intracapsular fractures of the femoral neck, the retinacular vessels are torn → interruption of the medial circumflex femoral supply → Avascular Necrosis (AVN) of the femoral head.

---

NERVE SUPPLY

• Femoral nerve (anterior)
• Obturator nerve (medial - also explains referred pain to knee in hip disease)
• Superior gluteal nerve (superior)
• Nerve to quadratus femoris (posterior)
• Nerve to rectus femoris (branch of femoral)

Hilton's Law in practice: Because the obturator nerve supplies both the hip joint and the knee joint, hip pathology in children (e.g. Perthes' disease, slipped upper femoral epiphysis) can present as knee pain - always examine the hip when a child complains of knee pain!

---

MOVEMENTS AND MUSCLES

• Iliofemoral ligament (prevents hyperextension - passive, no muscle effort)
• Gluteus medius + minimus (prevent pelvic tilt during single-leg stance)

---

BURSAE RELATED TO HIP JOINT

---

FACTORS MAINTAINING STABILITY

1. Deep socket - acetabulum deepened by the acetabular labrum; covers >half of femoral head
2. Strong ligaments - especially the iliofemoral (Y) ligament, the strongest ligament in the body
3. Atmospheric pressure - joint surfaces held together by atmospheric pressure (like a suction cup); negative intracapsular pressure
4. Muscles - especially iliopsoas anteriorly, glutei posteriorly and superiorly
5. Orientation of neck - femoral neck angle (125°) and anteversion (15°) direct the head into the acetabulum

---

APPLIED ANATOMY / CLINICAL NOTES (Snell Style)

---

1. Fracture of the Neck of Femur

• Common in: Elderly osteoporotic women (postmenopausal)
• Mechanism: Low-energy fall (trivial trauma due to weak bone)
• Clinical signs: Limb is shortened, externally rotated, and adducted
  • External rotation: psoas major loses its fulcrum (femoral head in acetabulum) → its unopposed pull rotates the distal fragment externally
  • Shortening: adductor group + psoas pull the proximal femur upward
• Types:
  • Intracapsular (subcapital, transcervical): Retinacular vessels torn → high risk of AVN of femoral head → treated by hemiarthroplasty / total hip replacement in elderly
  • Extracapsular (intertrochanteric, subtrochanteric): Retinacular vessels intact → less AVN risk → treated by dynamic hip screw (DHS) / internal fixation
• Osteoporosis predisposes - also causes vertebral and Colles' fractures

---

2. Avascular Necrosis (AVN) of the Femoral Head

• Caused by disruption of blood supply (mainly medial circumflex femoral artery)
• Causes: Intracapsular fracture (most common), corticosteroid use, sickle cell disease, alcohol abuse, Caisson disease (decompression sickness), Perthes' disease (in children)
• X-ray: Increased density, flattening, collapse of femoral head ("crescent sign")
• Treatment: Core decompression (early), total hip replacement (late)

---

3. Dislocation of the Hip Joint

• Mechanism: Dashboard injury - force applied along the axis of a flexed, adducted femur (e.g., knee hits dashboard in RTA)
• Clinical appearance: Limb is shortened, adducted, internally rotated (opposite of femoral neck fracture)
• Complication: Sciatic nerve injury (~10% of cases) - foot drop, sensory loss
• Emergency: Must reduce within 6 hours; AVN risk increases sharply with delay (>10 hours → 25% AVN)
• Reduction: Allis maneuver (in-line traction with 90° hip flexion)

• Mechanism: Forced abduction + extension
• Clinical appearance: Limb is abducted, externally rotated, slightly flexed
• Complication: Femoral nerve + vessel injury; avascular necrosis

---

4. Congenital Dislocation of the Hip (CDH) / Developmental Dysplasia of Hip (DDH)

• Failure of normal development of acetabulum, femoral head, or both
• More common in: Girls, first-born, breech presentation, family history
• Tests:
  • Ortolani's test: Abduction of flexed hip causes a "clunk" as dislocated femoral head reduces back into acetabulum
  • Barlow's test: Adduction causes femoral head to dislocate posteriorly out of the acetabulum
  • Galeazzi sign (Allis sign): Knee on affected side appears lower when hips and knees are flexed - due to limb shortening
• Treatment: Pavlik harness (< 6 months); surgery if delayed

---

5. Osteoarthritis of the Hip

• Degeneration of articular hyaline cartilage
• Symptoms: Groin pain, stiffness (especially morning stiffness), referred pain to knee (via obturator nerve)
• X-ray: Reduced joint space (superolateral area first), osteophytes, subchondral sclerosis, cysts
• Treatment: Analgesia, physiotherapy → total hip replacement (THR/THA)

---

6. Trendelenburg's Test

• Tests integrity of the hip abductor mechanism: gluteus medius + minimus + superior gluteal nerve
• Positive test (abnormal): When standing on the affected leg, the pelvis drops toward the normal (unsupported) side - because the abductors on the standing side cannot hold the pelvis level
• Causes of positive Trendelenburg:
  • Superior gluteal nerve palsy (e.g., following posterior approach hip surgery)
  • Gluteus medius/minimus wasting
  • Dislocation of the hip (abductor lever arm lost)
  • Coxa vara (reduced neck-shaft angle)
  • Paget's disease of the femur
• Trendelenburg gait: Patient lurches toward the affected side to compensate for pelvic drop ("compensated Trendelenburg")

---

7. Hip Joint Aspiration / Injection

• Approached anteriorly - just below the inguinal ligament, lateral to the femoral artery pulse
• Used for: septic arthritis drainage, corticosteroid injection for OA, aspiration of hemarthrosis
• The femoral artery (palpable midway between ASIS and pubic symphysis below inguinal ligament) serves as the landmark - needle inserted lateral to it

---

8. Referred Pain from the Hip Joint

• Due to obturator nerve innervating both the hip joint and knee joint
• Hip pathology → knee pain in children (Perthes' disease, SUFE)
• Always examine the hip when a child presents with knee pain and no obvious knee pathology

---

SUMMARY BOX (Quick Recall)

---

• Each question has 5 options (A–E)
• Answer one at a time
• I'll tell you if you're right or wrong and explain the answer
• We'll track your score

---

Question 1

✅ CORRECT! Score: 1/1

---

Question 2

---

HIP JOINT - MCQ Practice

(5 options each | MBBS 1st Year Pattern)

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

ANSWERS

---

---

GLUTEAL REGION

(Snell's Clinical Anatomy Format)

---

INTRODUCTION

• Superior: Iliac crest
• Inferior: Gluteal fold (transverse skin crease below buttock)
• Medial: Intergluteal cleft (sacrum and coccyx)
• Lateral: Greater trochanter of femur

• With pelvic cavity and perineum through the greater and lesser sciatic foramina
• Inferiorly, continuous with the posterior compartment of the thigh

---

GREATER AND LESSER SCIATIC FORAMINA

Greater Sciatic Foramen

• Greater sciatic notch of hip bone
• Sacrotuberous ligament
• Sacrospinous ligament

• Superior gluteal nerve and vessels

1. Sciatic nerve
2. Inferior gluteal nerve and vessels
3. Posterior cutaneous nerve of thigh
4. Pudendal nerve and internal pudendal vessels
5. Nerve to obturator internus (+ branch to gemellus superior)
6. Nerve to quadratus femoris (+ branch to gemellus inferior)
7. (Perforating cutaneous nerve - pierces sacrotuberous ligament directly)

Mnemonic for structures BELOW piriformis: "2 P's, 2 G's, 2 N's, 1 S"

• Pudendal nerve + internal Pudendal vessels
• inferior Gluteal nerve + inferior Gluteal artery
• Nerve to obturator internus + Nerve to quadratus femoris
• Sciatic nerve
• Posterior cutaneous nerve of thigh

Lesser Sciatic Foramen

• Lesser sciatic notch
• Sacrotuberous ligament
• Sacrospinous ligament

• Tendon of obturator internus (from pelvis to gluteal region)
• Pudendal nerve and internal pudendal vessels (re-entering perineum after briefly being in gluteal region)
• Nerve to obturator internus (same route as pudendal)

---

MUSCLES OF THE GLUTEAL REGION

SUPERFICIAL GROUP (Larger muscles - abductors and extensors)

---

---

---

---

---

DEEP GROUP (Small muscles - lateral rotators)

Mnemonic for deep lateral rotators (sup to inf): "P-OI-GS-GI-QF-OE" "Please Open Gently, Girls - Quite Exciting" Piriformis, Obturator Internus, Gemellus Superior, Gemellus Inferior, Quadratus Femoris, Obturator Externus

---

ILIOTIBIAL TRACT (ITB)

• A thickened longitudinal band of the deep fascia (fascia lata) on the lateral side of the thigh
• Formed by condensation of fascia lata + insertions of gluteus maximus (posterior) and TFL (anterior)
• Runs from iliac crest to Gerdy's tubercle on the anterolateral tibia
• Function: Stabilizes the knee in extension; acts as a lateral patellar retinaculum; transmits forces from gluteus maximus and TFL to the tibia

---

NERVES OF THE GLUTEAL REGION

1. Superior Gluteal Nerve (L4, L5, S1)

• Only nerve passing above piriformis
• Runs in the plane between gluteus medius and minimus
• Supplies: gluteus medius, gluteus minimus, tensor fasciae latae
• Clinical: Damage → abductor weakness → positive Trendelenburg sign → Trendelenburg gait

2. Inferior Gluteal Nerve (L5, S1, S2)

• Passes below piriformis
• Supplies: gluteus maximus only
• Clinical: Damage → weakness of hip extension; difficulty climbing stairs and rising from a chair

3. Sciatic Nerve (L4, L5, S1, S2, S3)

• Largest nerve in the body
• Passes below piriformis, midway between greater trochanter and ischial tuberosity
• Lies deep to gluteus maximus, in the plane between superficial and deep muscles
• Crosses posterior surfaces of: obturator internus + gemelli → quadratus femoris
• Exits gluteal region at lower border of quadratus femoris → enters posterior thigh
• Actually two nerves (tibial + common peroneal) in a common sheath
• Variation: In 10-12% of people, common peroneal component passes through or above piriformis (clinically important!)

4. Posterior Cutaneous Nerve of Thigh (S1, S2, S3)

• Below piriformis, medial to sciatic nerve
• Supplies skin over: lower gluteal region, posterior thigh, upper leg, perineum (via perineal branches)

5. Nerve to Quadratus Femoris (L4, L5, S1)

• Below piriformis, deep to sciatic nerve (anterior plane)
• Supplies: quadratus femoris + gemellus inferior + hip joint

6. Nerve to Obturator Internus (L5, S1, S2)

• Below piriformis, between posterior cutaneous nerve and pudendal nerve
• Gives branch to gemellus superior
• Passes over ischial spine → through lesser sciatic foramen → supplies obturator internus

7. Pudendal Nerve (S2, S3, S4)

• Most medial structure below piriformis
• Passes through greater sciatic foramen → briefly in gluteal region → hooks around ischial spine → through lesser sciatic foramen → enters perineum via Alcock's canal
• Supplies perineum (not gluteal region structures)

8. Perforating Cutaneous Nerve (S2, S3)

• Unique: does NOT pass through greater sciatic foramen
• Pierces the sacrotuberous ligament directly
• Supplies skin over medial lower gluteal region

---

ARTERIES OF THE GLUTEAL REGION

Superior Gluteal Artery

• Branch of internal iliac artery
• Passes above piriformis
• Divides into superficial and deep branches:
  • Superficial branch: Supplies gluteus maximus
  • Deep branch: Runs between gluteus medius and minimus; anastomoses with lateral circumflex femoral artery; supplies gluteus medius, minimus, TFL
• Contributes to trochanteric anastomosis

Inferior Gluteal Artery

• Branch of internal iliac artery
• Passes below piriformis
• Supplies gluteus maximus + deep group muscles + accompanies sciatic nerve (as the arteria comitans nervi ischiadici)
• Contributes to the cruciate anastomosis (with medial and lateral circumflex femoral arteries and 1st perforating artery)

---

PIRIFORMIS - THE KEY LANDMARK

• Hip extended: Lateral rotation of thigh
• Hip flexed (>90°): Abduction of thigh (reversal of action)

• Above piriformis: Superior gluteal nerve + vessels
• Below piriformis: Everything else (6 nerves + vessels)

---

BURSAE IN GLUTEAL REGION

---

APPLIED ANATOMY / CLINICAL NOTES

---

1. Intramuscular Injection in the Gluteal Region

• Divide the buttock into 4 quadrants with two imaginary lines:
  • Vertical line from highest point of iliac crest
  • Horizontal line midway between iliac crest and ischial tuberosity
• Inject in the UPPER OUTER (superolateral) quadrant - anterior corner
• The needle enters gluteus medius (not gluteus maximus)
• The sciatic nerve curves through the upper lateral corner of the lower medial quadrant

Important: The gluteal region extends anteriorly to the ASIS. The sciatic nerve lies in the lower medial quadrant. Never inject in the lower or medial quadrants.

• Palm on greater trochanter, index finger on ASIS, middle finger spreads toward posterior iliac crest - inject in the triangle formed

---

2. Sciatic Nerve Injury

• Badly placed intramuscular injection (lower medial quadrant)
• Posterior hip dislocation
• Fractures of pelvis/acetabulum
• Prolonged sitting on hard surface (pressure palsy)
• Pelvic tumors

• Loss of all movements below the knee (foot drop + inability to plantarflex)
• Loss of knee flexion (hamstrings paralyzed)
• Anaesthesia of leg and foot (except medial side - saphenous nerve from femoral)
• Loss of ankle jerk (tibial nerve territory)
• Foot drop (common peroneal territory)
• Knee extension is INTACT (femoral nerve, anterior compartment)

---

3. Superior Gluteal Nerve Injury

• Paralysis of gluteus medius + minimus + TFL
• Trendelenburg sign: Pelvis drops to opposite (normal) side when standing on affected leg
• Trendelenburg gait (Compensated): Patient lurches toward the affected side while walking to bring the body's center of gravity over the stance leg

---

4. Inferior Gluteal Nerve Injury

• Paralysis of gluteus maximus
• Difficulty climbing stairs, rising from a chair, or running (all require powerful hip extension)
• Ordinary level walking is relatively unaffected (hamstrings compensate)
• Characteristic "gluteus maximus lurch" in gait

---

5. Piriformis Syndrome

• Piriformis muscle becomes hypertrophied, inflamed, or goes into spasm
• Compresses the sciatic nerve (especially in the 10-12% of people where the common peroneal component passes through the muscle)
• Symptoms: Deep buttock pain + sciatica-like pain radiating down the leg
• Mimics: Lumbar disc prolapse (L4-S1)
• Difference from disc prolapse: Straight leg raise may be negative; symptoms worse with sitting; no back pain; no neurological signs of disc (reflexes intact)
• Treatment: Physiotherapy, local injection, rarely surgical release

---

6. Variation of Sciatic Nerve and Piriformis

• Passes through the piriformis (most common variant)
• Or passes above the piriformis

---

SUMMARY TABLE

---

QUICK RECALL BOX

---

---