Week 12 Flashcards
(236 cards)
Where can cranial nerve abnormalities arise from?
communicating pathways to and from the cortex, cerebellum and other parts of brainstem nerve nucleus nerve neuromuscular junction disorders muscle
What are the mnemonics for cranial nerves?
On old olympus towering tops a frenchman and german viewed some hops.
some say marry money but my brother says bug business makes money
What are the 12 cranial nerves?
olfactory optic oculomotor trochlear trigeminal abducens facial vestibulocochlear glossopharyngeal vagus spinal accessory hypoglossal
Describe the olfactory nerve
sensory
smell
olfactory cells of nasal muscosa - olfactory bulbs - pyriform cortex
Describe the optic nerve
sensory
vision
retinal ganglion cells - optic chiasm - thalamus- primary visual cortex in occipital cortex
How do you examine the optic nerve?
optic discs with opthalmascope
pupillary responses
visual acuity
visual fields and blind spot (tested by confrontation)
Describe the oculomotor nerve
motor midbrain movement of eyeball, lens accommodation inferior oblique, superior, middle and inferior recti muscles levator palpeerde superiores
part 2 - parasympathetic
midbrain *Edinger_westphal)
pupil constriction
ciliary muscle and pupillary constrictor muscles
Describe the appearance of an oculomotor palsy
eye turns down and out - superior oblique and lateral rectus are the only muscles active
ptosis
involvement of pupil only if complete palsy
Describe the trochlear nerve
motor
moves eyeball
midbrain (inferior colliculus)
superior oblique muscles
depresses the adducted eye and introits the abducted eye
longest intracranial course
II and IV are only nerves to decussate to contralateral side
Describe the abducens nerve
motor
eyeball movement
pons
lateral rectus muscles
Describe an abducens nerve palsy
most common CN palsy
lateral rectus
double vision when looking to affected side - horizontal diplopia
Describe internuclear opthalmoplegia
disorder of conjugate gaze
failure of adduction of affected eye with nystagmus on lateral gaze in contralateral eye
can be unilateral or bilateral
results from lesion of medial longitudinal fasiculus (connects III and iV nerve nuclei)
commonly seen in MS
What does horner’s system consist of?
miosis
ptosis
apparent enopthalmos
anhidrosis
What can cause horner’s syndrome?
results from ipsilateral disruption of cervical/thoracic sympathetic chain congenital brainstem stroke cluster headache apical lung tumour MS carotid artery dissection cervical rib syringomyelia
Describe the trigeminal nerve
1 - sensory input from face
pons and medulla
face (opthalmic, mandibular and maxillary divisors) and anterior 2/3 of tongue
2 - motor
mastication
pons
masseter, temporalis, medial and lateral pterygoids
Describe the facial nerve
1 - motor
pons
muscles of expression
2 - sensory
medulla
taste
anterior 2/3 of tonguw
3 - parasympathetic
medula
salivation and lacrimation
Describe the corneal reflex
useful in patients with reduced conscious level lightly touch cornea with cotton wool afferent - V efferent - VII test of pontine function
Describe the vestibulocochlear nerve
1 - sensory
balance
pons and medulla
nerve endings within semi-circular canals - cerebellum and spinal cord
2 - sensory
hearing
pons and medulla
cochlear - auditory cortex in the temporal lobes
Describe the glossopharangeal nerve
1 - sensory
medulla
taste, proprioception for swallowing, blood pressure receptors
posterior 1/3 of tongue, pharyngeal nerve and carotid sinuses
2 - motor
medulla
swallow and gag reflex
pharyngeal muscles and lacrimal glands
3 parasympathetic
saliva production
parotid glands
In a glossopharyngeal palsy, in what direction does the uvula deviate to?
away from the side of the lesion
Describe the vagus nerve
1 - sensory
medulla
chemorecptors, pain receptors, sensation
blood oxygen concentration, carotid bodies, respiratory and digestive tracts, external ear, larynx and pharynx
2 - motor
medulla
hert rate and stroke volume, peristalsis, air-flow, speech and swallowing
pacemaker and ventricular muscles, smooth muscles of GI tract, smooth muscles of bronchial tube, muscles of larynx and pharynx
3 - parasympathetic
smooth muscles and glands of the same areas innervated by motor component as well as the thoracic and abdominal areas
Describe the spinal accessory nerve
motor
head rotation and shoulder shrugging
medulla
sternocleidomastoid and trapezius muscles
Describe the hypoglossal nerve
motor
speech and swallowing
medulla
tongue
In what direction does a hypoglossal nerve palsy cause the tongue to deviate?
towards the affected side