Cranial Nerve Examination

A cranial-nerve examination is a map, not a checklist. The 12 paired nerves sample smell, vision, eye movement, facial sensation and expression, hearing and balance, swallowing and voice, shoulder and neck strength, and tongue control. Because these pathways travel through the cortex, brainstem, skull base, orbit, and peripheral tissues, the pattern of abnormal findings can help localize disease before imaging identifies its cause. At the bedside, adapt the examination to the patient's history, acuity, cooperation, and baseline. Compare sides, account for glasses and hearing aids, and document what was actually tested rather than recording a vague “cranial nerves intact.” A new fixed pupil, sudden facial or speech change, deteriorating consciousness, or impaired airway protection is not a cue to finish a routine checklist; it is a cue to stabilize, escalate, and activate the appropriate emergency pathway. The sections that follow connect each bedside maneuver with the nerve it tests, the pattern it may reveal, and the finding that changes priority.