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Gross Anatomy and Embryology Flashcards

7 cards from real NBME practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Gross Anatomy and Embryology flashcards as text

  1. A patient presents with inability to abduct the arm beyond 15 degrees after a humeral surgical neck fracture. Which nerve is most likely injured?

    Answer: Axillary nerve

    The axillary nerve wraps around the surgical neck of the humerus and innervates the deltoid, which is responsible for arm abduction beyond 15 degrees.

  2. During embryonic development, failure of the pleuroperitoneal membrane to close results in which congenital defect?

    Answer: Congenital diaphragmatic hernia

    Failure of the pleuroperitoneal membranes to fuse closes off the pericardioperitoneal canals, and incomplete closure allows abdominal viscera to herniate into the thorax.

  3. A patient with Colles fracture develops inability to oppose the thumb. Which structure is most likely compressed at the wrist?

    Answer: Median nerve in carpal tunnel

    Colles fracture can cause swelling that compresses the median nerve in the carpal tunnel, impairing thenar muscles responsible for thumb opposition.

  4. Which embryonic structure gives rise to the adrenal cortex?

    Answer: Intermediate mesoderm

    The adrenal cortex derives from intermediate mesoderm (specifically the mesothelium lining the posterior abdominal wall), while the medulla derives from neural crest cells.

  5. A stab wound to the posterior triangle of the neck results in weakness of shoulder elevation and head rotation. Which nerve is damaged?

    Answer: Accessory nerve (CN XI)

    The accessory nerve (CN XI) traverses the posterior triangle and innervates the trapezius (shoulder elevation) and sternocleidomastoid (head rotation).

  6. During cardiac embryology, the interventricular septum forms primarily from which structure?

    Answer: Muscular septum growing from apex plus membranous portion from cushions

    The muscular interventricular septum grows up from the ventricular apex, and the membranous portion is completed by tissue from the endocardial cushions (atrioventricular septal tissue).

  7. A patient cannot extend the wrist or fingers after a midshaft humeral fracture. Which nerve is injured?

    Answer: Radial nerve

    The radial nerve runs in the spiral groove of the mid-humerus and innervates all wrist and finger extensors; midshaft fractures commonly injure it.