Cranial Nerve - Damage & Symptoms

Olfactory Nerve (CN I)

Anosmia (partial or total loss of smell)

Optic Nerve (CN II)

Anopsia (visual defects)

Facial Nerve (VII)

Decreased tearing (dry eye) and decreased salivation (dry mouth); loss of taste sensation to anterior 2/3 of tongue and/or facial nerve palsy characterized by paralyzed facial muscles, lack of obicularis oculi contraction, sagging at corner of mouth

Vestibulocochlear (CN VIII)

Lesions in vestibular branch produce loss of balance, nausea, committing, and dizziness; lesions in cochlear branch result in deafness

Vagus (CN X)

Paralysis leads to a variety of larynx problems, including hoarseness, monotone voice, or complete loss of voice. Other lesions may cause difficulty in swallowing or impaired gastrointestinal system mobility

Abducens Nerve (CN VI)

Paralysis of lateral rectus limits lateral movement of eye; diplopia (double vision)

Trochlear Nerve (CN IV)

Paralysis of superior oblique, leading to strabismus (eye not in parallel/deviated improperly), diplopia (double vision)

Accessory Nerve (CN XI)

Paralysis of trapezius and sternocleidomastoid, resulting in difficulty in elevation shoulder or turning head to opposite site (sternocleidomastiod function)

Oculomotor Nerve (CN III)

Ptosis (upper eyelid droop); paralysis of most eye muscles, leading to strabismus (eyes not parallel/deviated improperly), diplopia (double vision), focusing difficulty

Glossopharyngeal (IX)

Reduced salivary secretion (dry mouth); loss of state sensations to posterior 1/3 of tongue

Hypoglossal Nerve (CN XII)

Swallowing and speech difficulties due to impaired tongue movement; if a single hypoglossal nerve is paralyzed, a protruded tongue deviates to the side of the damaged nerve

Trigeminal Nerve (CN V)

Trigeminal Neuralgia (tic douloureux) is caused by inflammation of the sensory components of the trigeminal nerve and results in intense, pulsation pain lasting from minutes to several hours