Psychiatric-Mental Health Nurse Practitioner (PMHNP) Purple Book Practice Test

Protruding the tongue directly tests the nerve that controls tongue movements. The hypoglossal nerve (cranial nerve XII) innervates all intrinsic tongue muscles and the main extrinsic tongue muscles like the genioglossus, which drives protrusion. When you ask someone to stick out their tongue, you’re checking whether these muscles can contract properly under voluntary control. If the hypoglossal nerve is affected, the tongue may deviate toward the weaker side or show weakness, fasciculations, or atrophy. The other nerves listed govern different functions: glossopharyngeal and vagus are involved in swallowing and palate elevation; trigeminal governs jaw movements and facial sensation. So tongue protrusion is a clear test of CN XII, confirming the role of the hypoglossal nerve in this exam activity.