Anatomy Flashcards
7 cards from real USMLE practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Anatomy flashcards as text
Which cranial nerve exits the skull through the foramen ovale?
Answer: Mandibular nerve (CN V3)
The mandibular nerve (V3) exits through the foramen ovale; V1 exits through the superior orbital fissure, V2 through the foramen rotundum, and CN VII through the stylomastoid foramen.
A patient presents with weakness of finger abduction and adduction, loss of sensation over the medial 1.5 fingers and hypothenar eminence, and a 'claw hand' deformity affecting primarily the ring and little fingers. Which nerve is most likely injured?
Answer: Ulnar nerve
The ulnar nerve innervates the interossei (finger abduction/adduction), hypothenar muscles, and provides sensation to the medial 1.5 fingers; injury causes claw hand due to loss of intrinsic muscle function.
The blood-testis barrier, which protects developing germ cells from immune surveillance, is formed by tight junctions between which cells?
Answer: Sertoli cells
Sertoli cells form tight junctions with each other to create the blood-testis barrier, separating developing spermatocytes from the systemic immune system.
Which of the following structures is located in the posterior mediastinum?
Answer: Thoracic duct
The thoracic duct ascends through the posterior mediastinum alongside the descending thoracic aorta, esophagus, and azygos vein before draining into the left subclavian vein.
A 68-year-old man presents with progressive hoarseness. Imaging reveals a large aortic arch aneurysm. Which nerve is most likely compressed by this aneurysm?
Answer: Left recurrent laryngeal nerve
The left recurrent laryngeal nerve hooks under the aortic arch in the thorax, making it susceptible to compression from aortic arch aneurysms or mediastinal masses causing hoarseness.
Which muscle is responsible for 'unlocking' the knee from full extension to allow flexion to begin?
Answer: Popliteus
The popliteus unlocks the knee from full extension by internally rotating the tibia on a fixed femur (screw-home reversal), allowing knee flexion to initiate.
Which of the following structures does NOT pass through the carpal tunnel?
Answer: Ulnar nerve
The ulnar nerve passes through Guyon's canal (ulnar canal) at the wrist, not the carpal tunnel; the carpal tunnel contains the median nerve and 9 flexor tendons (4 FDS, 4 FDP, 1 FPL).