USMLE Anatomy 2

Question 1

A patient sustains a fibular neck fracture and subsequently develops foot drop with loss of sensation over the dorsum of the foot. Which nerve was most likely injured?

Accepted Answer

Common fibular (peroneal) nerve

Answer

The common fibular nerve winds superficially around the fibular neck, making it highly susceptible to injury; it innervates dorsiflexors and evertors of the foot, and its injury produces foot drop.

Question 2

Which of the following structures correctly passes through the inguinal canal in males?

Accepted Answer

Ilioinguinal nerve and spermatic cord

Answer

In males, the inguinal canal transmits the spermatic cord along with the ilioinguinal nerve; in females, the round ligament of the uterus passes through instead of the spermatic cord.

Question 3

When performing a lumbar puncture at L4-L5, which sequence of structures does the needle correctly traverse from superficial to deep?

Accepted Answer

Skin → supraspinous ligament → interspinous ligament → ligamentum flavum → epidural space → dura mater → subdural space → arachnoid mater → subarachnoid space

Answer

A lumbar puncture needle traverses in order: skin, supraspinous ligament, interspinous ligament, ligamentum flavum, epidural space, dura mater, subdural space, and arachnoid mater before entering the subarachnoid space.

Question 4

A patient develops a 'winged scapula' following a radical mastectomy with axillary dissection. Which nerve was most likely damaged during the procedure?

Accepted Answer

Long thoracic nerve

Answer

The long thoracic nerve innervates the serratus anterior; its injury during mastectomy or axillary dissection causes winging of the scapula as the medial border protrudes from the thoracic wall.

Question 5

The sinoatrial (SA) node receives its arterial supply from the SA nodal artery, which arises from which vessel in approximately 60% of individuals?

Accepted Answer

Right coronary artery

Answer

In approximately 60% of individuals, the SA nodal artery arises from the right coronary artery; in the remaining ~40%, it arises from the left circumflex artery.

USMLE Practice Test

USMLE Practice Test

USMLE Anatomy 2