Atlas of Human Anatomy by Netter

FACTS & HINTS

High-Yield Facts

Clinical Points

Facial Nerve Palsy

Unilateral (one-sided) injury to the facial nerve or its branches

Results in sudden weakness affecting some or all of facial muscles on affected side

Causes include: infections such as TB, polio; brainstem lesions; tumors, such as acoustic neuromas; acute and sudden exposure of the

face to cold temperatures

Angle of mouth droops on affected side with dribbling of food and saliva

Sad look when face is relaxed

Lower eyelid falls away from eyeball with drying of cornea and tearing from corner of eye

Speech affected (production of B,M,P, and W sounds), because of weakened lip muscles

Trigeminal Neuralgia

Disease affecting the sensory root of CN V

Characterized by episodes of intense pain lasting a few seconds in areas innervated by the trigeminal nerve.

Usually one-sided and can affect a division of CN V, usually the mandibular, maxillary nerve.

Pain can be triggered by touching a sensitive area ("trigger point")

The cause is not usually known

Treatment is directed to controlling the pain.

Ocular Nerve Palsy

A lesion of the oculomotor nerve will paralyze all extraocular muscles except the lateral rectus and the superior oblique. This leads to :

Ptosis-drooping of the eyelid (levator palpebrae superioris)

No constriction of the pupil in response to light (sphincter pupillae)

Dilation of the pupil (unopposed dilator pupillae)

Eyeball abducted and depressed ("down and out") (unopposed lateral rectus and superior oblique)

No accommodation of the lens for near vision (ciliary muscle)

page 75

page 76

Mnemonics

Memory Aid
Names of the Cranial Nerves

"On Old Olympus Towering Tops A Few Virile Germans Viewed Ample Of Hops"

I: On - Olfactory

II: Old - Ophthalmic

III: Olympus - Oculomotor

IV: Towering - Trochlear

V: Tops - Trigeminal

VI: A - Abducent

VII: Few - Facial

VIII: Virile - Vestibulocochlear

IX: Germans - Glossopharyngeal

X: Viewed - Vagus

XI: Ample - Accessory

XII: Hops - Hypoglossal

Memory Aid
Motor, Sensory and Mixed (Both) Cranial Nerves

"Some Say Marry Money But My Brother Says Bad Business Marry Money"

I: Olfactory Sensory

II: Optic Sensor

III: Oculomotor Motor

IV: Trochlear Motor

V: Trigeminal Both

VI: Abducent Motor

VII: Facial Both

VIII: Vestibulocochlear Sensory

IX: Glossopharyngeal Both

X: Vagus Both

XI: Accessory Motor

XII: Hypoglossal Motor