L:\usmle review 7 - Sinoe medical homepage.

(A)
(B)
(C)
(D)
(E)
Facial
Glossopharyngeal
Hypoglossal
Trigeminal
Vagus
43. The correct answer is E. The recurrent laryngeal nerves are branches of the vagus (CN X)
and supply all intrinsic muscles of the larynx except the cricothyroid. The right recurrent laryngeal
nerve recurs around the right subclavian artery. The left recurrent laryngeal nerve recurs in the
thorax around the arch of the aorta and ligamentum arteriosum. Both nerves ascend to the larynx
by passing between the trachea and esophagus, near the thyroid gland. The recurrent laryngeal
nerves are therefore particularly vulnerable during thyroid surgery, and damage may cause
extreme hoarseness.
The facial nerve (choice A) innervates the muscles of facial expression, the stapedius muscle,
and the lacrimal, submandibular and sublingual glands. It also mediates taste sensation from the
anterior two thirds of the tongue.
The glossopharyngeal nerve (choice B) innervates the stylopharyngeus muscle and the parotid
gland. Visceral afferents supply the carotid sinus baroreceptors and carotid body chemoreceptors,
and mediate taste from the posterior one third of the tongue. Somatosensory fibers supply pain,
temperature, and touch information from the posterior one third of the tongue, upper pharynx,
middle ear, and eustachian tube.
The hypoglossal nerve (choice C) innervates the intrinsic muscles of the tongue, the
genioglossus, hypoglossus, and styloglossus muscles.
The trigeminal nerve (choice D) receives sensory information from the face and innervates the
muscles of mastication.
44. A 54-year-old African-American woman undergoes a routine insurance physical examination.
Chest x-ray film reveals bilateral hilar masses. Biopsy of the masses shows granulomata, but