Cranial Nerve Testing Guide

Overview

This lecture demonstrates a step-by-step process for testing all 12 cranial nerves during a clinical examination.

Ask the patient to smile to test facial muscle movement (facial nerve, CN VII).
Have the patient show their teeth and grit them to further assess facial muscles.
Instruct the patient to puff out their cheeks and resist pressure to evaluate facial nerve strength.
Ask the patient to push their tongue against the inside of each cheek; apply resistance to check hypoglossal nerve (CN XII).
Have the patient stick out their tongue and observe for deviation to assess hypoglossal nerve function.
Test sensation on the face ("can you feel this?") for trigeminal nerve (CN V).
Test hearing ("can you hear that?") for vestibulocochlear nerve (CN VIII) in each ear.
Instruct the patient to shrug shoulders to assess spinal accessory nerve (CN XI).
Ask the patient to raise eyebrows to further assess facial nerve (CN VII).
Direct the patient to follow your finger with only their eyes, including moving toward the nose, to test oculomotor, trochlear, and abducens nerves (CN III, IV, VI).
Ask the patient to open their mouth and use a tongue blade to inspect the uvula and test gag reflex for glossopharyngeal and vagus nerves (CN IX, X).

Cranial Nerves — Twelve paired nerves exiting the brainstem, each controlling specific sensory and motor functions.
Facial Nerve (CN VII) — Controls facial muscle movement and expression.
Trigeminal Nerve (CN V) — Responsible for facial sensation and mastication muscles.
Hypoglossal Nerve (CN XII) — Controls tongue movements.
Vestibulocochlear Nerve (CN VIII) — Governs hearing and balance.
Spinal Accessory Nerve (CN XI) — Innervates shoulder and neck muscles.
Oculomotor, Trochlear, Abducens Nerves (CN III, IV, VI) — Control most eye movements.
Glossopharyngeal & Vagus Nerves (CN IX, X) — Involved in gag reflex and swallowing.