NBME Gross Anatomy and Embryology 4

Question 1

A patient presents with deviation of the uvula to the right, hoarseness, and dysphagia after a posterior inferior cerebellar artery stroke. Which nerve is most directly affected at the level of the medulla?

Accepted Answer

CN X (vagus)

Answer

Lateral medullary (Wallenberg) syndrome affects CN X nuclei, causing ipsilateral palatal and vocal cord paralysis with uvular deviation away from the lesion.

Question 2

Branchial cleft cysts in the lateral neck most commonly arise from which pharyngeal cleft?

Accepted Answer

Second

Answer

The second pharyngeal cleft normally obliterates but may persist as a cyst along the anterior border of the sternocleidomastoid, which is the most common branchial cleft cyst.

Question 3

A patient cannot wrinkle the forehead on the left side and has drooping of the left corner of the mouth. Which structure is most likely damaged?

Accepted Answer

Left CN VII at the stylomastoid foramen (lower motor neuron)

Answer

Lower motor neuron CN VII lesions (e.g., Bell palsy) affect all ipsilateral facial muscles including the forehead, unlike upper motor neuron lesions which spare forehead wrinkling due to bilateral cortical representation.

Question 4

The thyroid gland descends from the foramen cecum to its final position. Remnants of this descent may persist as which structure?

Accepted Answer

Thyroglossal duct cyst

Answer

The thyroglossal duct normally obliterates after the thyroid descends; persistence creates a midline cyst that moves upward with swallowing and tongue protrusion.

Question 5

After parotid gland surgery, a patient develops flushing and sweating over the cheek during meals. Which nerve is responsible for this Frey syndrome?

Accepted Answer

Auriculotemporal nerve (branch of CN V3)

Answer

Frey syndrome occurs when regenerating parasympathetic fibers from the auriculotemporal nerve aberrantly innervate sweat glands, causing gustatory sweating.

NBME Practice Test

NBME Practice Test

NBME Gross Anatomy and Embryology 4