What is the method to test the trigeminal nerve?

The trigeminal nerve, also known as cranial nerve V, is primarily responsible for sensation in the face and motor functions such as biting and chewing. To effectively test this nerve, it is important to assess its sensory distribution, which includes the forehead, cheeks, and jawline. By touching different areas of the face, the practitioner can evaluate the sensory pathways and determine whether the nerve is functioning correctly.

This method is specific to the trigeminal nerve, as the other options target different nerves or functions. For example, smiling, frowning, and other facial movements assess the facial nerve, while testing hearing pertains to the vestibulocochlear nerve. Swallowing or repeating phrases is related to the glossopharyngeal and vagus nerves. Therefore, the approach of touching the forehead, cheeks, and jawline is the correct method for assessing the integrity of the trigeminal nerve specifically.