Cranial Nerves 12 pairs PNS You must know

Cranial Nerves � 12 pairs � PNS � You must know: The name The number The order The function S/M How to assess

Cranial Nerves �Names of nerves On old olympus’ towering tops a Finn and German viewed some Hops ▪ ▪ Olfactory Optic Oculomotor Trochlear Trigeminal Abducens Facial Acoustic Glaossopharyngeal Vagus Spinal accessory Hypoglossal

Cranial Nerves �Classification by Function Sensory, Motor or Both ▪ Some say marry money but my brother says bad business marry money ▪ ▪ ▪ Olfactory S Optic S Oculomotor M Trochlear M Trigeminal B Abducens M Facial B Acoustic S Glossopharyngeal B Vagus B Spinal accessory M Hypoglossal M

Cranial Nerves � Number -1 � Name: Olfactory � Sensory � Function Sense of smell � Assessment Identify familiar odor

Cranial nerves – 1 Olfactory �Sense of smell Rarely formally tested Ask directly Bedside foodstuffs

Olfactory • “Have you had any change in your sense of smell recently? ” • Can use coffee/orange smells to see if correctly identified. • Not routinely examined in clinical practice.

Cranial nerves – 2 Optic �Visual acuity Snellen chart, newspaper �Visual fields �Direct light reflex �(Consensual light reflex)

Cranial Nerves � Number -2 � Name: Optic � Sensory � Function Visual Acuity � Assessment Snellen eye chart

Pupil Retina Optic nerve III Optic chiasm Lateral geniculate bodies Ciliary ganglion Edinger-Westfahl nucleus Pretectal nucleus

L R Visual fields Retina Optic nerve Optic chiasm Bitemporal hemianopia Optic radiation RIGHT homonymous hemianopia

Examples of How to Examine

Pupil Abnormalities � Asymmetry of pupil size of >1 mm suggests CN III compression � Bilateral dilation suggests anoxia or drug affect � Unilateral constriction is seen with sympathetic dysfunction (Horner syndrome) or carotid artery dissection � Bilateral constriction is seen with: Pontine hemorrhage Drugs (opiates, Clonidine) Toxins (organophosphates)

Cranial Nerves � Number -3 � Name: Oculomotor � Motor � Function Muscles the move the eye, lid, papillary constriction, lens accommodation � Assessment Test for ocular rotation, nystagmus, Papillary reflexes, check for ptosis

Oculomotor, Abducens and Trochlear • “Keeping you head perfectly still, follow my finger with your eyes. ” • Make a H pattern with your finger. • “Do you see double anywhere? ” • Look for nystagmus.

� Nystagmus: Involuntary osculation of the eyeball

� Ptosis Drooping eyelid

Ptosis

� Papillary reflexes Pupil changing in size when exposed to light

VI nerve palsy

Cranial Nerves � Number -5 � Name: Trigeminal � Sensory & Motor � Function Facial sensation, corneal reflex, mastication � Assessment Distinguish between sharp and dull on face Check blink reflex Have patient clinch and move jaw from side to side, feel jaw strength

Trigeminal Nerve • Two parts: - Sensory to face Motor to muscles of mastication • Assess sensation to face • Determine if patient can open mouth. • “Clench your teeth” - feel for muscle bulk at Masseters

V 1 - Opthalmic V 2 - Maxillary V 3 - Mandibular

Cranial Nerves � Number - 7 � Name: Facial � Sensory & Motor � Function Facial expression and muscle movement Salivation and tearing Taste Sensation in the ear � Assessment Observe for symmetry while pt performs facial movement Stick out tongue Distinguish between sugar and salt

Facial Nerve • Must assess at least 3 muscle groups • “Raise your eyebrows” • “Show me your teeth” • “Puff out your cheeks”

VII. Facial �UMN paralysis-Only lower face affected Stroke �LMN paralysis-All of face affected Bells Palsy

Bell’s Palsey. What side is affected? Can she wrinkle her forehead on the right?

Central VII Peripheral VII

Bell’s palsy � Symptoms of Bell's palsy may include: � Numbness, mild weakness or complete paralysis on one side of the face; � A droopy face on one side, with difficulty making facial expressions, smiling on that side or closing the eye on that side of the face; � Drooling; � Pain in or behind your ear or around the jaw on the affected side; � Increased sensitivity to sound; � Excessive tearing in the eye or dry eye; � Headache or neck pain; � Loss of the ability to taste.

Cranial Nerves � Number -8 � Name: Acoustic � Sensory � Function Hearing & equilibrium � Assessment Simple hearing test

Cranial Nerves � Number -9 � Name: Glossopharyngeal � Sensory & Motor � Function Taste Sensation in pharynx and tongue Pharyngeal muscles � Assessment Ability to discriminate btw sugar and salt

Cranial Nerves Palate and Tongue: Glossopharyngeal (IX), Vagus (X) Ask patient to say “ah” www. heartandstroke. ca/profed

Glossopharyngeal and Vagus • Open your mouth. • Say “arrgh” • Look at palatal movement. Deviates AWAY from affected side. • Assess gag reflex - not routinely done

Cranial Nerves � Number -11 � Name: Accessory � Motor � Function Shoulder movement � Assessment Strength of muscle, shrug

Accessory • Put hand on one cheek, “push me away”, and feel sternocleidomastoid bulk on opposite side.

Cranial Nerves � Number -12 � Name: Hypoglossal � Motor � Function Tongue movement � Assessment Check tongue strength and movement

Hypoglossal • “Stick out your tongue” • Look for deviation TOWARDS affected side. • Can assess power, but only if deficit found on gross examination.