• Inferior surface of the brain as it appears on gross dissection.

Nerves in nasal cavity synapse within olfactory bulbs.

The Olfactory nerve (I) – for sense of smell. Sensory

Anosmia – loss of smell.

The Optic nerve (II) - visual information. Sensory

50-50 cross over

Anopsias – visual defects.

6 Extrinsic Eye Muscles

4 Rectus Muscles 2 Oblique Muscles

Nose here

oblique

oblique

rectus

rectus

The Oculomotor nerve (III) - Controls 4 of

the 6 extrinsic muscles of the eye.

The Trochlear nerve (IV)– Innervates superior oblique eye muscle.

Motor

Motor

External Strabismus – lateral drift. Ptosis.

Largest cranial nerve

1) Ophthalmic branch

skin, lacrimal gland

• The Trigeminal nerve (V)

2) Maxillary branchlower eyelid, upper jaw

3) Mandibular branch

tongue, lower teeth

Has 3 Branches

Mixed

e.g., Tic Douloureux.

The Facial nerve (VII)Controls muscles of scalp and facial

expression.Muscles of mastication and speech.

The Abducens nerve (VI)Innervates lateral rectus muscle of eye (abduction!)

Pressure sensations from face.Taste sensations from anterior 2/3 of tongue.

Motor

Mixed

Internal Strabismus – cross eyed.

e.g., Bell’s palsy.

The Facial nerve (VII) Mixed

The Vestibulocochlear nerve (VIII)– Sense of balance, position and body movement.

– Sense of sound (hearing).

Sensory

Loss of balance, nausea, vomiting.

Deafness.

The Glossopharyngeal nerve (IX)

Controls swallowing

Taste sensation from posterior 1/3 tongue.

Detects O2 and CO2 content of bloodin carotid artery.

Mixed

Impairment of taste and swallowing.

Vital to autonomic control of visceral function

The Vagus nerve (X) Mixed

Hoarseness

of voice.

Impaired

regulation

of heart.Impaired

G.I. tract

motility.

Controls vocal folds

Regulates heart Controls

G.I. Tract

The Accessory nerve (XI)– Internal branch

Innervates swallowing muscles.

The Hypoglossal nerve (XII)Voluntary food mixing, swallowing and speech.

Control of tongue movements.

– External branch

Controls sternocleidomastoid and trapezius.

Motor

Motor

Impaired shrugging.Turn toward injured side.

Impaired swallowing. Deviating tongue (atrophy).

• The Accessory nerve (XI) and Hypoglossal nerve (XII)