Here are all 20 answers to your Anatomy-I MCQ paper:

1. Pisiform bone, which is a sesamoid bone, develops in the tendon of: Answer: A. Flexor carpi ulnaris The pisiform is a sesamoid bone that develops within the tendon of flexor carpi ulnaris.

2. Which nerve pierces coracobrachialis? Answer: D. Musculocutaneous nerve The musculocutaneous nerve pierces the coracobrachialis muscle as it enters the anterior compartment of the arm.

3. A 35-year-old man with undue prominence of the medial border of the right scapula and difficulty in overhead abduction. Name the nerve injured: Answer: B. Long thoracic nerve The long thoracic nerve (nerve to serratus anterior, C5-C7) injury causes winging of the scapula - the medial border becomes prominent and overhead abduction is impaired.

4. A 45-year-old man suffered a direct injury on the back of the leg close to the short saphenous vein, with tingling and numbness over the lateral part of the leg. Which nerve is injured? Answer: B. Sural nerve The sural nerve runs close to the short (small) saphenous vein in the posterior leg and supplies sensation to the lateral aspect of the leg and foot.

5. A 47-year-old house maid who spends hours on her knees doing household chores - which bursa is most likely affected? Answer: B. Prepatellar bursa The prepatellar bursa lies anterior to the patella and is inflamed by prolonged kneeling ("housemaid's knee"). Suprapatellar and anserine bursae are not directly over the kneeling pressure point.

6. Femoral artery is a direct continuation of: Answer: C. External iliac artery The femoral artery begins as the continuation of the external iliac artery at the level of the inguinal ligament.

7. During gastrulation, which structure induces formation of intraembryonic mesoderm? Answer: A. Primitive streak The primitive streak is the structure through which epiblast cells migrate to form intraembryonic mesoderm during gastrulation (week 3).

8. Meckel's diverticulum is a remnant of: Answer: C. Vitello intestinal duct Meckel's diverticulum is a persistent remnant of the vitello-intestinal (omphalomesenteric) duct. It follows the "rule of 2s."

9. Which of the following bone violates the Law of ossification? Answer: B. Fibula The law of ossification states that a bone ossifies from the end that is last to fuse (i.e., the primary centre appears at the end that fuses last). The fibula is an exception - its lower end ossifies first but fuses last, violating this law.

10. The neuroglial cells that form myelin sheaths in the peripheral nervous system are: Answer: B. Schwann cells Schwann cells form myelin in the PNS. Oligodendrocytes form myelin in the CNS. Astrocytes and microglial cells have different functions.

11. MRI scan through the transpyloric plane includes all the following structures EXCEPT: Answer: A. Fundus of gall bladder The transpyloric plane (L1) passes through the neck/body of the gallbladder, not the fundus. The fundus typically lies at the tip of the right 9th costal cartilage, which is slightly below the transpyloric plane. Structures at L1 include: neck of pancreas, origin of portal vein, duodenojejunal flexure, and the hila of kidneys.

12. Ileocolic artery is a branch of: Answer: B. Superior mesenteric artery The ileocolic artery is a branch of the superior mesenteric artery, supplying the terminal ileum, caecum, and appendix.

13. The total rotation of the midgut is: Answer: D. 270 degrees clockwise The midgut rotates a total of 270 degrees counter-clockwise (anticlockwise) around the superior mesenteric artery axis. However, if the question asks as seen from the front/from the perspective of the gut looking outward, some texts phrase it as 270 degrees anticlockwise. Answer: C. 270 degrees anticlockwise is the standard answer in most embryology texts.

14. Which structure is NOT a boundary of the trigone of bladder? Answer: A. Urachus The trigone of the bladder is bounded by the two ureteric orifices (posterolaterally) and the internal urethral orifice (anteriorly). The urachus is not a boundary - it is the median umbilical ligament, a remnant of the allantois, attached to the apex of the bladder.

15. A newborn male with urethral opening along the ventral surface of the penis. This condition is called: Answer: B. Hypospadias Hypospadias is the abnormal opening of the urethra on the ventral (under) surface of the penis. Epispadias is on the dorsal surface.

16. Which structure is crossed by the uterine artery 2 cm lateral to the cervix? Answer: D. Ureter The uterine artery crosses over the ureter at approximately 2 cm lateral to the cervix - a surgically important relation (remembered as "water under the bridge"). The ureter is at risk of injury during hysterectomy.

17. The root of the mesentery does NOT cross which structure? Answer: C. Right renal vessels The root of the mesentery extends from the duodenojejunal flexure (upper left) to the ileocaecal junction (lower right), crossing the horizontal part of the duodenum, abdominal aorta, inferior vena cava, right ureter, and right psoas major. It does NOT cross the right renal vessels.

18. Gall bladder is lined by: Answer: D. Simple columnar with brush border The gallbladder mucosa is lined by simple tall columnar epithelium with a brush border (microvilli), which aids in absorption and concentration of bile.

19. Elastic cartilage is found in: Answer: C. Epiglottis Elastic cartilage is found in the epiglottis, pinna of the ear, and auditory tube. Intervertebral discs contain fibrocartilage, costal cartilage is hyaline cartilage, and the glenoid labrum is fibrocartilage.

20. Longitudinal bundles of smooth muscle in tunica adventitia is a feature of: Answer: C. Large sized vein Large veins (like the inferior vena cava, portal vein) characteristically have longitudinal smooth muscle bundles in their tunica adventitia - a distinctive histological feature that differentiates them from arteries.