OSCE On-Ground Practice Test

Testing the hypoglossal nerve focuses on the tongue’s motor function. Since this nerve controls the tongue muscles, you assess how the tongue moves and what signs appear on the tongue itself. When the patient sticks out the tongue, a normal tongue stays midline. If there’s weakness on one side, the tongue deviates toward the weaker side. You also look for fasciculations (twitches) and atrophy (wasting) of the tongue muscles, which signal denervation from a hypoglossal nerve issue. These signs—fasciculations, atrophy, and deviation—together reflect CN XII function. The gag reflex and tongue sensation involve other cranial nerves (glossopharyngeal/vagus and trigeminal), hearing and balance involve the vestibulocochlear nerve, and visual fields involve the optic nerve, so they aren’t part of CN XII testing.