Cranial Nerves

III 1 V VI 2 VII VIII 3 IX 4 XI 5 XII

1 2 IV 3 4 6 5 7 9 8 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 Nucleus in midbrain Innervates 4 extraocular muscles and functions in most eye movements Contains parasympathetic which innervates pupillary constrictor muscles and ciliary muscle of lens. Trochlear Nucleus in midbrain Nerve exits dorsal surface and crosses over Moves eye medially and downward Abducens Nucleus in pons Moves eye laterally

Cranial Nerve V: Trigeminal Nerve 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 VII: Facial 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

Facial Nerve Lesions cause paralysis in face Bell’s Palsy Facial nerve is impaired and then gradually recovers. Cause unknown,(viral or inflammatory)

Cranial Nerve VIII: Vestibulocochlear Nerve Auditory and vestibular sensation Travels with facial nerve Branches go to cochlea, vestibule

Vestibular and Cochlear Sensory Organs

Lesions in Auditory Pathway During auditory seizures: patients often report tones from the side opposite the cortical area involved in the seizure. Vertigo can be caused by damage to vestibular pathways

Cranial Nerve IX: Glossopharyngeal Nerve 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 X: Vagus 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 XI: Spinal Accessory Nerve Motor : sternomastoid upper trapezius muscles

Cranial Nerve XII: Hypoglossal Nerve Motor function: intrinsic and extrinsic tongue muscles.