Cranial Nerves

Cranial Nerves

1

2

3

4

III

VI

V

VII VIII

5

IX

XIXII

IV

1

2

34

5 6

7

89

10

Cranial Nerve 1: Olfactory Nerve

Anosmia

• Patients complain of loss of taste.

• Head injury is a common cause.

Cranial Nerve II: Optic Nerve

Cranial Nerves III, IV, VI: Oculomotor, Trochlear, Abducens

Trochlear• Nucleus in midbrain• Nerve exits dorsal surface and crosses over• Moves eye medially and downward

Oculomotor• Nucleus in midbrain• Innervates 4 extraocular muscles and functions in most eye movements• Contains parasympathetic which innervates pupillary constrictor musclesand ciliary muscle of lens.

Abducens• Nucleus in pons• Moves eye laterally

• Trigeminal ganglion • Ophthalmic, maxillary and mandibular divisions

• Sensory: Touch, pain, temp, proprioception for face, mouth,• anterior 2/3 of tongue, nasal sinuses.• Motor: Muscles of chewing, tensor tympani muscle

Cranial Nerve V: Trigeminal Nerve

• Motor function: muscles of facial expression.

• Parasympathetic function: innervation of lacrimal glands and some salivary gland.

• Visceral sensory function: taste from anterior 2/3 of tongue

Cranial Nerve VII: Facial Nerve

Facial Nerve Lesionscause paralysis in face

Bell’s Palsy Facial nerve is impaired and then gradually recovers. Cause unknown,(viral or inflammatory)

• Auditory and vestibular sensation

• Travels with facial nerve• Branches go to cochlea, vestibule

Cranial Nerve VIII: Vestibulocochlear Nerve

Vestibular and Cochlear Sensory Organs

Lesions in Auditory Pathway

1. During auditory seizures: patients often report tonesfrom the side opposite the cortical area involved in the seizure.

2. Vertigo can be caused by damage to vestibular pathways

• Motor function: stylopharyngeus muscle which elevates pharynx during talking and swallowing and participates in gag reflex.

• Parasympathetic function: innervation of parotid salivary gland.

• Visceral sensory function: taste from posterior1/3 of tongue

Cranial Nerve IX: Glossopharyngeal Nerve

• Motor function: pharyngeal muscles (swallowing) & laryngeal muscles (vocalization)

• Parasympathetic function: innervation of heart, lungs, most if digestive tract.

• Somatic sensation function: sensation from pharynx, meninges, external auditory meatus.

Cranial Nerve X: Vagus Nerve

Motor : sternomastoid upper trapezius muscles

Cranial Nerve XI: Spinal Accessory Nerve

Motor function: intrinsic and extrinsic tongue muscles.

Cranial Nerve XII: Hypoglossal Nerve