Anatomy & Histology · patient case question

All of the following cranial nerves participate in swallowing EXCEPT:

Patient case: Cranial nerves, radiation safety and the diabetic patient

Scenario: Three items spanning anatomy, radiology and medicine.

Show answer and explanation

Correct answer: A. XI (accessory)

A. Correct — this is the exception. The accessory nerve supplies sternocleidomastoid and trapezius, muscles of head and shoulder movement. It plays no part in the swallow.
B. The facial nerve does participate: it supplies the muscles that seal the lips and control the oral phase, along with the posterior belly of digastric and stylohyoid.
C. The glossopharyngeal nerve does participate: it carries sensation from the oropharynx that triggers the swallow reflex and supplies stylopharyngeus.
D. The vagus does participate, supplying the pharyngeal constrictors and the muscles of the soft palate and larynx through the pharyngeal plexus.

Note: Trigeminal (V) and hypoglossal (XII) are also involved — V for the muscles of mastication and mylohyoid, XII for tongue movement.