Cranial Nerve Examination Flashcards
Cranial Nerve l: Olfactory Nerve
- type: sensory/motor/parasympathetic? [1]
- function? [1]
- tract? [3]
- how to examine? [1]
- Sensory nerve
- Smell
- Olfactory cells of nasal mucosa → olfactory bulbs → pyriform cortex
- Ask patient if there has been any changes in their sense of smell
Cranial Nerve lI: Optic Nerve
- type: sensory/motor/parasympathetic? [1]
- function? [1]
- tract? [4]
- how to examine? [7]
- Sensory nerve
- Vision
- Retinal ganglion cells → optic chiasm → thalamus → primary visual cortex in occipital lobe
- Examination:
- Optic discs with ophthalmoscope
- Pupillary responses
- Pupillary reflexes
- Swinging light test
- Visual acuity (using Snellen chart)
- Visual fields and blind spot (tested by confrontation)
- Eye muscles and movement
What is the abnormality seen in the following ophthalmoscopic image and what features lead you to this diagnosis? [4]
- Papilloedema
- haemorrhage
- obscuration of blood vessels
- blurring of disc margins
What is the abnormality seen in the following opthalmascopic image and what features lead you to this diagnosis? [2]
- optic atrophy/neuritis
- pale optic disc
What is used to test visual acuity? [1]
Snellen Chart
Describe how each eye muscle moves the eye
Cranial Nerve III: Oculomotor → the motor component:
- Nucleus name & location? [2]
- Functions? [2]
- Structures innervated? [5]
- Nucleus:
- oculomotor nucleus
- found in midbrain
- Functions:
- movement of eyeball
- lens accommodation
- Structures innervated:
- inferior oblique muscle
- superior rectus muscle
- medial rectus muscle
- inferior rectus muscle
- levator palpebrae superioris muscle
Cranial Nerve III: Oculomotor → the parasympathetic component:
- Nucleus name & location? [2]
- Function? [1]
- Structures innervated? [2]
- Nucleus:
- Edinger-Westphal nucleus
- found in midbrain
- Function:
- pupil constriction
- Structures innervated:
- ciliary muscle
- pupillary constrictor muscles
What is the diagnosis? [1]
Complete left oculomotor nerve palsy
Cranial Nerve IV: Trochlear
- type: sensory/motor/parasympathetic? [1]
- functions? [2]
- nucleus location? [2]
- structure innervated? [1]
- Motor nerve
- Functions:
- moves eyeball
- depresses the adducted eye
- intorts the abducted eye
- Nucleus location:
- inferior colliculus of midbrain
- Structure innervated:
- superior oblique muscle
What is unique about cranial nerves II and IV? [1]
II and IV are only nerves to decussate to contralateral side
Cranial Nerve VI: Abducens
- type: sensory/motor/parasympathetic? [1]
- functions? [1]
- nucleus location? [1]
- structure innervated? [1]
- Motor nerve
- Function:
- eyeball movement to the side
- Nucleus:
- pons
- Structure innervated:
- lateral rectus muscles
What is the diagnosis? [1]
left abducens nerve palsy
What is internuclear ophthalmoplegia, what does it result from and what condition is it commonly associated with? [3]
- Disorder of conjugate gaze which presents as failure of adduction of affected eye with nystagmus on lateral gaze in contralateral eye and can be unilateral or bilateral
- Results from lesion of medial longitudinal fasciculus (connects 3rd and 6th nerve nuclei)
- Commonly seen in multiple sclerosis
Describe Horner’s Syndrome:
- symptoms? [4]
- causes? [9]
- Symptoms:
- Miosis
- Ptosis
- Apparent enophthalmos
- Anhidrosis
- Causes/Pathogenesis:
- Results from ipsilateral disruption of cervical/thoracic sympathetic chain:
- Congenital
- Brainstem stroke
- Cluster headache
- Apical lung tumour
- Multiple sclerosis
- Carotid artery dissection
- Cervical rib
- Syringomyelia
- Results from ipsilateral disruption of cervical/thoracic sympathetic chain: