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Answer all the mcqs
Reading File
These are anatomy MCQs from ABVMU MBBS First Year. Let me answer all 20 directly from knowledge - these are classic anatomy questions with well-established answers.
Here are the answers to all 20 MCQs:
ABVMU Human Anatomy Paper II - MCQ Answers (Set A)
Q1. A stab injury at the root of the neck damages the left phrenic nerve. Which is most likely to occur?
Answer: (A) Loss of sensation over the central diaphragmatic pleura and paralysis of the left hemidiaphragm
The phrenic nerve (C3, C4, C5) provides motor supply to the ipsilateral hemidiaphragm and sensory supply to the central diaphragmatic pleura. Damage causes ipsilateral hemidiaphragm paralysis and loss of sensation over the central pleura/pericardium on the same side.
Q2. The azygos vein arches over which structure before opening into the superior vena cava?
Answer: (B) Root of left lung
Wait - the azygos vein arches over the root of the right lung before draining into the SVC.
Answer: (A) Root of right lung
Q3. A patient with mitral stenosis develops compression of the esophagus. Which chamber of the heart is enlarged?
Answer: (A) Left atrium
The left atrium is the most posterior cardiac chamber and lies directly anterior to the esophagus. Mitral stenosis causes left atrial enlargement, which compresses the esophagus posteriorly (demonstrated on barium swallow as posterior indentation).
Q4. Which bronchopulmonary segment is least likely to be affected in aspiration while lying supine?
Answer: (B) Posterior segment of upper lobe
When supine, aspiration preferentially goes to the superior (apical) segment of the lower lobe and posterior segment of the upper lobe - but the question asks which is LEAST affected. The apical segment of lower lobe (C) is actually most affected in supine position. The medial basal segment of lower lobe (D) and posterior segment of upper lobe are less dependent.
Answer: (B) Posterior segment of upper lobe
Actually, when supine, the most dependent segments are the superior (apical) segment of the lower lobe and the posterior segments. The segment LEAST likely to be affected is the (B) Posterior segment of upper lobe - as this is the most commonly affected while upright/lateral, not supine.
Correction: In supine position, aspiration goes to superior segment of lower lobe (right side). The LEAST affected would be (A) Superior segment of lower lobe is most affected; the least affected is (B) Posterior segment of upper lobe is affected when lateral recumbent. The correct answer is (D) Medial basal segment of lower lobe as it is not dependent in any position.
Answer: (D) Medial basal segment of lower lobe
Q5. The ligamentum arteriosum is derived from:
Answer: (B) Left sixth arch artery
The ligamentum arteriosum is the fibrous remnant of the ductus arteriosus, which develops from the left sixth pharyngeal arch artery.
Q6. A patient presents with caput medusae. Which veins are involved?
Answer: (A) Paraumbilical and superficial epigastric veins
Caput medusae results from portal hypertension causing reversal of flow through paraumbilical veins (which connect the portal system to the anterior abdominal wall veins - superficial epigastric, thoracoepigastric veins), creating visible dilated veins radiating from the umbilicus.
Q7. The bare area of the liver is directly related to the:
Answer: (A) Diaphragm
The bare area of the liver (on its posterior/superior surface) is devoid of peritoneal covering and is directly applied to the diaphragm, with which it is in direct contact.
Q8. Failure of 270° counterclockwise rotation of the midgut results in:
Answer: (A) Malrotation
Normal midgut rotation is 270° counterclockwise. Failure of this rotation results in malrotation of the gut, which can present with volvulus, obstruction, and Ladd's bands.
Q9. The marginal artery of Drummond is formed by anastomosis between branches of:
Answer: (A) Superior and inferior mesenteric arteries
The marginal artery of Drummond (marginal artery of the colon) runs along the mesenteric border of the large intestine and is formed by anastomoses between branches of the superior mesenteric artery (ileocolic, right colic, middle colic) and inferior mesenteric artery (left colic, sigmoid).
Q10. The linea pectinata of the anal canal represents the junction between:
Answer: (A) Endoderm and ectoderm
The pectinate (dentate) line marks the junction between the endodermal hindgut (upper anal canal) and the ectodermal proctodeum (lower anal canal). Above = endoderm; below = ectoderm.
Q11. During a radical hysterectomy, the surgeon must identify the structure passing beneath the uterine artery:
Answer: (A) Ureter
The ureter passes beneath (under) the uterine artery - remembered by the mnemonic "water (ureter) under the bridge (uterine artery)." This is a critical surgical landmark to avoid ureteric injury during hysterectomy.
Q12. A patient has loss of sensation over the posterior thigh following pelvic trauma. Which nerve is injured?
Answer: (A) Posterior femoral cutaneous nerve
The posterior femoral cutaneous nerve (S1, S2, S3) provides sensory innervation to the posterior thigh, perineum, and posterior scrotum/labia. Loss of sensation over the posterior thigh indicates injury to this nerve.
Q13. The obturator canal transmits:
Answer: (A) Obturator nerve and vessels
The obturator canal (opening in the obturator membrane) transmits the obturator nerve and obturator vessels (artery and vein) from the pelvis to the medial thigh.
Q14. A fracture of the neck of femur is most likely to damage which artery supplying the head of the femur in adults?
Answer: (A) Medial circumflex femoral artery
The medial circumflex femoral artery is the primary blood supply to the femoral head in adults (via retinacular vessels). It is most vulnerable in femoral neck fractures, leading to avascular necrosis of the femoral head. (The lateral circumflex is a distractor - it mainly supplies the trochanters.)
Q15. Trendelenburg gait is caused by paralysis of:
Answer: (A) Gluteus medius and minimus
Trendelenburg gait occurs when the gluteus medius and minimus (abductors of the hip, supplied by superior gluteal nerve) are paralyzed. The pelvis drops to the opposite (unsupported) side during the stance phase.
Q16. The tarsal tunnel contains all of the following EXCEPT:
Answer: (C) Dorsalis pedis artery
The tarsal tunnel (behind the medial malleolus, under flexor retinaculum) transmits: Tibialis posterior tendon, Flexor digitorum longus tendon, Posterior tibial artery and veins, Tibial nerve, and Flexor hallucis longus tendon (mnemonic: Tom, Dick, And Very Nervous Harry). The dorsalis pedis artery is on the dorsum of the foot and does NOT pass through the tarsal tunnel.
Q17. Which type of epithelium lines the urinary bladder?
Answer: (A) Transitional epithelium (Urothelium)
The urinary bladder is lined by transitional epithelium (urothelium), which allows distension and contraction. It is unique to the urinary tract (renal pelvis, ureters, bladder, proximal urethra).
Q18. The blood-air barrier of the lung does NOT include:
Answer: (A) Type II pneumocyte cytoplasm
The blood-air barrier consists of: Type I pneumocyte cytoplasm + fused basal lamina + capillary endothelial cell cytoplasm. Type II pneumocytes produce surfactant but are NOT part of the blood-air barrier (they are cuboidal, not thin/flat like Type I cells).
Q19. A karyotype of 47, XX, +21 is due to:
Answer: (A) Meiotic nondisjunction
Trisomy 21 (Down syndrome) with karyotype 47, XX, +21 is most commonly caused by meiotic nondisjunction (failure of chromosomes to separate during meiosis I or II), most often in the maternal egg.
Q20. A male with Klinefelter syndrome is most likely to have which of the following karyotypes?
Answer: (B) 47, XXY
Klinefelter syndrome is the most common sex chromosome aneuploidy in males. The classic karyotype is 47, XXY - one extra X chromosome. These individuals are phenotypically male but have small testes, infertility, and gynecomastia.
Summary Table
| Q | Answer | Key Point |
|---|---|---|
| 1 | (A) | Phrenic nerve = ipsilateral hemi-diaphragm paralysis + central pleural sensation |
| 2 | (A) | Azygos arches over root of RIGHT lung |
| 3 | (A) | Left atrium (posterior) compresses esophagus in mitral stenosis |
| 4 | (D) | Medial basal segment - least dependent in any position |
| 5 | (B) | Ductus arteriosus = left 6th arch artery remnant |
| 6 | (A) | Paraumbilical + superficial epigastric veins = caput medusae |
| 7 | (A) | Bare area of liver related to diaphragm |
| 8 | (A) | Failed 270° rotation = malrotation |
| 9 | (A) | Marginal artery = SMA + IMA anastomosis |
| 10 | (A) | Pectinate line = endoderm-ectoderm junction |
| 11 | (A) | Ureter passes under uterine artery ("water under the bridge") |
| 12 | (A) | Posterior femoral cutaneous nerve = posterior thigh sensation |
| 13 | (A) | Obturator canal = obturator nerve and vessels |
| 14 | (A) | Medial circumflex femoral artery = main supply to femoral head |
| 15 | (A) | Trendelenburg = gluteus medius and minimus paralysis |
| 16 | (C) | Dorsalis pedis NOT in tarsal tunnel |
| 17 | (A) | Bladder = transitional epithelium |
| 18 | (A) | Type II pneumocyte NOT part of blood-air barrier |
| 19 | (A) | Trisomy 21 = meiotic nondisjunction |
| 20 | (B) | Klinefelter = 47, XXY |
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Answer these mcqs
Here are the answers to all 20 MCQs from Set D:
ABVMU Human Anatomy Paper II - Set D Answers
Q1. A patient undergoes surgery for a mass in the posterior mediastinum. The surgeon accidentally injures the thoracic duct. Which finding is most likely?
Answer: (B) Chylous pleural effusion due to leakage of lymph
The thoracic duct carries chyle (lymph + dietary fat) from the cisterna chyli upward through the posterior mediastinum. Injury causes chyle to leak into the pleural cavity, producing a chylothorax - a chylous pleural effusion. This is a well-known complication of posterior mediastinal surgery.
Q2. A surgeon performing a coronary bypass identifies an artery running in the anterior interventricular groove. This artery is:
Answer: (C) Anterior interventricular artery (LAD)
The anterior interventricular groove lodges the anterior interventricular artery (also called the left anterior descending artery - LAD), a branch of the left coronary artery. The posterior interventricular groove contains the posterior interventricular artery (from RCA in right dominance).
Q3. A patient has enlargement of the left atrium causing difficulty in swallowing. The structure compressed is:
Answer: (B) Esophagus
The left atrium is the most posterior cardiac chamber and lies directly anterior to the esophagus. Left atrial enlargement (classically in mitral stenosis) compresses the esophagus, causing dysphagia - demonstrated as a posterior indentation on barium swallow.
Q4. A newborn presents with severe cyanosis. Echocardiography shows abnormal division of the truncus arteriosus. The embryological structure affected is:
Answer: (B) Neural crest cells
The aorticopulmonary septum that divides the truncus arteriosus into the aorta and pulmonary trunk is formed by neural crest cells (specifically cardiac neural crest cells). Abnormal migration/proliferation of neural crest cells leads to conditions like persistent truncus arteriosus and transposition of great vessels.
Q5. A histological specimen of the heart shows branching fibers, central nuclei and intercalated discs. The tissue is:
Answer: (C) Cardiac muscle
These are the three defining histological features of cardiac muscle:
- Branching fibers (unlike skeletal which are parallel)
- Central nuclei (skeletal muscle has peripheral nuclei)
- Intercalated discs (unique to cardiac muscle - contain gap junctions and desmosomes)
Q6. A patient with carcinoma of the head of pancreas develops obstructive jaundice. The tumour most likely compresses:
Answer: (B) Common bile duct
The common bile duct runs in the groove on the posterior surface of the head of the pancreas before entering the duodenum at the hepatopancreatic ampulla. Carcinoma of the head of pancreas classically compresses the CBD, causing painless progressive obstructive jaundice (Courvoisier's sign).
Q7. A surgeon performing splenectomy must be careful because the splenic artery runs along the:
Answer: (A) Superior border of pancreas
The splenic artery (largest branch of the celiac trunk) runs a tortuous course along the superior border of the pancreas before entering the splenorenal ligament to reach the spleen. This makes it vulnerable during pancreatic and splenic surgery.
Q8. A patient develops severe pain in the right shoulder after irritation of the diaphragm. The referred pain occurs through:
Answer: (B) Phrenic nerve
The phrenic nerve (C3, C4, C5) supplies the diaphragm and the central diaphragmatic pleura/peritoneum. Irritation of the diaphragm (e.g., by blood, air, or subphrenic abscess) causes referred pain to the shoulder (C4 dermatome) via the phrenic nerve - this is classic "shoulder tip pain."
Q9. During embryological development, the appendix is derived from:
Answer: (B) Midgut
The midgut gives rise to the distal duodenum, jejunum, ileum, cecum, appendix, ascending colon, and proximal two-thirds of transverse colon. The appendix specifically develops as an outgrowth of the cecal bud, which is a midgut derivative.
Q10. A patient has a persistent connection between ileum and umbilicus causing fecal discharge from the umbilicus. The anomaly is due to persistence of:
Answer: (B) Vitellointestinal (omphalomesenteric) duct
The vitellointestinal duct (omphalomesenteric duct) normally obliterates by week 7 of development. Persistence can result in:
- Patent vitellointestinal duct → fecal/enteric discharge from umbilicus
- Meckel's diverticulum (most common)
- Umbilical sinus or cyst
Q11. A woman undergoing pelvic surgery develops urinary complications due to injury to a structure passing near the uterine artery. Which structure is injured?
Answer: (B) Ureter
Classic surgical pearl: "Water under the bridge" - the ureter passes beneath the uterine artery at the base of the broad ligament, approximately 2 cm lateral to the cervix. This is the most common site of ureteric injury during hysterectomy.
Q12. The main lymphatic drainage of the ovary is to:
Answer: (C) Para-aortic lymph nodes
The ovary drains lymph via lymphatics that follow the ovarian vessels (gonadal vessels) to the para-aortic (lumbar) lymph nodes at the level of L1-L2, near the renal vessels. This is clinically important in ovarian cancer staging. (Note: the uterus/cervix drains to iliac nodes, but the ovary follows the gonadal vessels to para-aortic nodes.)
Q13. A patient has weakness of plantar flexion and loss of sensation on the sole of the foot. The injured nerve is:
Answer: (B) Tibial nerve
The tibial nerve (L4-S3) supplies:
- All muscles of the posterior compartment of leg (plantar flexors) and intrinsic muscles of the sole
- Sensation to the sole of the foot (via medial and lateral plantar nerves) Injury causes loss of plantar flexion and absent sensation on the sole.
Q14. A patient suffers posterior dislocation of the hip joint. The nerve most commonly injured is:
Answer: (C) Sciatic nerve
Posterior dislocation of the hip is the most common type (>90%), typically from dashboard injuries. The sciatic nerve runs posterior to the hip joint and is most vulnerable - injury occurs in up to 10-20% of posterior hip dislocations. It causes foot drop and sensory loss below the knee.
Q15. A runner develops pain due to inflammation of a bursa located between the skin and tibial tuberosity. This is:
Answer: (B) Infrapatellar bursitis
The superficial infrapatellar bursa lies between the skin and the tibial tuberosity (lower part of the patellar ligament insertion). Inflammation from repetitive kneeling or running causes infrapatellar bursitis. (Prepatellar bursa = "housemaid's knee," lies over the patella itself.)
Q16. The structure passing through the adductor hiatus is:
Answer: (A) Femoral artery and vein
The adductor hiatus is a gap in the lower end of the adductor magnus muscle. The femoral artery and vein pass through it from the adductor canal (subsartorial canal) into the popliteal fossa, where they become the popliteal artery and vein. The saphenous nerve exits separately above the hiatus.
Q17. A biopsy from the small intestine shows tall columnar cells with brush border and goblet cells. These cells are:
Answer: (A) Enterocytes
The small intestinal epithelium is composed of:
- Enterocytes (absorptive cells) - tall columnar cells with a prominent brush border (microvilli) for absorption
- Goblet cells (mucus secreting) - mixed in among enterocytes
The question describes the overall lining dominated by enterocytes with goblet cells mixed in.
Q18. A congenital anomaly results from failure of fusion of the Müllerian ducts. The most likely abnormality is:
Answer: (B) Bicornuate uterus
The Müllerian (paramesonephric) ducts fuse in the midline to form the uterus, cervix, and upper vagina. Failure of fusion results in a bicornuate uterus (two uterine horns). Complete non-fusion gives uterus didelphys; partial non-fusion gives bicornuate uterus.
Q19. A child has a mutation affecting collagen type I synthesis. Which disorder is most likely?
Answer: (B) Osteogenesis imperfecta
Collagen type I is the most abundant collagen in bone, tendons, and skin. Mutations in COL1A1 or COL1A2 genes cause osteogenesis imperfecta (brittle bone disease), characterized by fragile bones, blue sclerae, and hearing loss. (Marfan syndrome involves fibrillin-1; Down syndrome is trisomy 21.)
Q20. A female patient has short stature, webbed neck, and streak ovaries. The chromosomal abnormality is:
Answer: (B) 45, XO
This is the classic description of Turner syndrome - 45, X (monosomy X). Features include: short stature, webbed neck (pterygium colli), shield chest, streak gonads (causing primary amenorrhea and infertility), coarctation of aorta, and horseshoe kidney.
Summary Table
| Q | Answer | Key Point |
|---|---|---|
| 1 | (B) | Thoracic duct injury → chylous pleural effusion |
| 2 | (C) | Anterior interventricular groove = LAD (anterior interventricular artery) |
| 3 | (B) | Left atrium enlargement → esophageal compression |
| 4 | (B) | Truncus arteriosus divided by neural crest cells |
| 5 | (C) | Branching fibers + central nuclei + intercalated discs = cardiac muscle |
| 6 | (B) | Head of pancreas cancer compresses common bile duct |
| 7 | (A) | Splenic artery runs along superior border of pancreas |
| 8 | (B) | Diaphragmatic irritation → shoulder pain via phrenic nerve |
| 9 | (B) | Appendix is a midgut derivative |
| 10 | (B) | Fecal umbilical discharge = patent vitellointestinal duct |
| 11 | (B) | Ureter passes under uterine artery - most common hysterectomy injury |
| 12 | (C) | Ovary drains to para-aortic lymph nodes |
| 13 | (B) | Tibial nerve = plantar flexion + sole sensation |
| 14 | (C) | Posterior hip dislocation → sciatic nerve injury |
| 15 | (B) | Skin to tibial tuberosity bursa = infrapatellar bursa |
| 16 | (A) | Adductor hiatus transmits femoral artery and vein |
| 17 | (A) | Tall columnar + brush border + goblet cells = enterocytes |
| 18 | (B) | Failed Müllerian duct fusion = bicornuate uterus |
| 19 | (B) | Collagen type I mutation = osteogenesis imperfecta |
| 20 | (B) | Short stature + webbed neck + streak ovaries = Turner syndrome (45, XO) |
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