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 Assessment 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 Visual fields Snellen chart, newspaper Visual fields Direct light reflex (Consensual light reflex)

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

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

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

Examples of How to Examine

Pupil Abnormalities Asymmetry of pupil size of >1mm 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 Assessment 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: Assess sensation to face 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

V1 - Opthalmic V2 - Maxillary V3 - Mandibular

Cranial Nerves Assessment 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 Assessment 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” Ask the patient to say “ah”. The palate should move upwards symmetrically. Asymmetry of movement may be associated with dysarthria and dysphagia. Swallowing difficulties can be associated with aspiration after stroke. 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 Assessment 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 Assessment 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.