5. Cranial nerves Flashcards
intro to cranial nerve exam
“today I’ve been asked to examine you to see how well your your cranial nerves are working- these are the nerves that supply your nose, eyes, face, ears, mouth and neck”
“so this will involve me checking things like your vision, eye movements, facial movements and your hearing…”
“does that sound okay?”
“are you in any pain at all?”
general inspection CN exam
Scars, neurofibromas, facial asymmetry, ptosis, proptosis, skew deviation of the eyes or inequality of the pupils.
smell CN exam
Cranial nerve I - Olfactory - “any recent change to sense of smell?”, if needed do smell tests in each nostril, other one occluded
Eyes CN exam
Vision - Cranial nerve II - Optic - “any changes to vision? Do you wear glasses or contact lenses?”
Visual acuity (>2 fingers, EO)
confrontation (visual fields) (2 fingers, EO),
attention (2 fingers),
accommodation (1 finger),
direct and consensual light reflexes (no fingers)
Movement - Cranial nerves III, IV, VI - SO4LR63 - H shape, I shape, “double vision?” “Pain on moving your eyes?” look for nystagmus
to complete eye CN exam
“I would also like to do ophthalmoscopy and check colour vision”
Face CN exam
Cranial nerve V - Trigeminal Sensation in three regions, motor : clench jaw whilst palpating temples and mandible, open jaw against resistance
Cranial nerve VII - Facial facial expressions: raise eyebrows, close eyes, close eyes against resistance, puff cheeks, purse lips, show teeth
which muscle does occulomotor nerve supply
everything except superior oblique and lateral rectus therefore:
Levator palpebrae superioris - raises the upper eyelid.
Superior rectus muscle - rotates the eyeball backward, “looking up”
Medial rectus muscle - adducts the eye, “looking towards your nose”
Inferior rectus muscle - rotates the eyeball forwards, “looking down”
which muscle does abducens nerve supply
lateral rectus
LR6
which muscles does the trochlear nerve supply
superior oblique
SO4
which eye muscles do each of the nerves supply
SO4LR63
SO4 - superior oblique 4th CN so trochlear
LR6 - lateral rectus 6th cranial nerve so abducens
3 - everyrthing else - 3rd CN - occulomotor
ears CN exam
Cranial nerve VIII - Vestibulocochlear - cover opposite ear whisper a number at 15cm and 60cm. If abnormality → rinnes and webers
mouth CN exam
Cranial nerve IX and X -Glossopharyngeal and vagus: change to voice? issues swallowing? note hoarseness, open mouth and say “ahh” - look at uvula. swallow a sip of water
Cranial nerve XII - Hypoglossal: observe tongue, protrusion of tounge, tongue to cheek against resistance
shoulders CN exam
Cranial nerve XI - accessory shrug shoulders against resistance, turn head against resistance
tounge hypoglossal
intrinsic muscles - shape and size for example, in tongue rolling – and have a role in facilitating speech, eating and swallowing.
extrinsic muscles except palatoglossus (innervated by vagus)
vagus tounge
palatoglossus muscle (an extrinsic muscle)
elevation of the posterior tounge
anterior 2/3 sensation and taste tounge
sensation: trigeminal nerve (CNV)
taste: facial nerve
posterior 1/3 of tounge sensation and taste
both glossopharyngeal nerve CNIX
tounge innervation
motor
- hypoglossal except for posterior tounge vagus (palatoglossus muscle)
sensation
- ant 2/3 trigeminal
- post 1/3 glossopharyngeal
taste
- ant 2/3 facial
- post 1/3 glossophayrngeal
how to test hypoglossal nerve
Ask the patient to open their mouth and inspect the tongue for any wasting or fasciculation
Ask the patient to protrude the tongue and move from side to side
tounge against cheek against resistance
innervation of gag reflex
The afferent limb of the gag reflex is the glossopharyngeal nerve, and the efferent limb is the vagus nerve.
examination of glossophayrngeal and vagus
open mouth and say “ahh” - look at uvula
swallow a sip of water
change to voice? issues swallowing?
uvula deviation?
uvula deviates away from site of lesion in X
presentation vagus nerve pasly
ipsilateral paralysis of the soft palate, pharynx, and larynx. The voice is hoarse or nasal, the involved palatal arch is paralyzed, and liquids will enter the nasopharynx or trachea. The vocal cord on the involved side is paralyzed.
refractory tachycardia
