Week 12 - Neurology Flashcards
What are the names of the 12 cranial nerves?
I- olfactory II- optic III- oculomotor IV- trochlear V- trigeminal VI- abducens VII- facial VIII- vestibulocochlear IX- glossopharyngeal X- vagus XI- spinal accessory XII- hypoglossal
What is the component & function of the olfactory nerve?
- Component: Sensory
- Function: Smell
What is the tract of olfactory nerve?
Olfactory cells of nasal mucosa –> Olfactory bulbs –> pyriform cortex
What is the component & function of the optic nerve?
- Component(s): Sensory
- Function: Vision
What is the tract of optic nerve?
Retinal ganglion cells –> optic chiasm –> thalamus –> primary visual cortex in occipital lobe
What 4 examinations should you do to assess the optic nerve?
- Optic discs with ophthalmoscope
- Pupillary responses
- Visual acuity (using Snellen chart)
- Visual fields & blind spot (tested by confrontation)
What are the 2 components & functions of the oculomotor nerve?
- Component 1: Motor
- Function 1: movement of eyeball & lens accommodation
- Component 2: Parasympathetic
- Function 2: pupil constriction
What are the 2 nuclei locations of the oculomotor nerve?
- Midbrain oculomotor
2. Midbrain Edinger-Westphal
What structures are innervated by the motor component of the oculomotor nerve?
- Inferior oblique, superior, medial & inferior recti muscles
- Levator palpebrae superioris
What structures are innervated by the parasympathetic component of the oculomotor nerve?
Ciliary muscle & pupillary constrictor muscles
What is the component & function of the trochlear nerve?
- Component: Motor
- Function: Moves eyeball
What is the nucleus location of the trochlear nerve?
Midbrain (inferior colliculus)
What structure is innervated by the trochlear nerve?
Superior oblique muscles
What eye movements does the Superior oblique muscles provide?
Depresses the adducted eye & intorts the abducted eye
What cranial nerve has the longest intracranial course?
Trochlear nerve
What 2 cranial nerves decussate to contralateral side?
II and IV
What is the component & function of the abducens nerve?
- Component: Motor
- Function: Eyeball movement
Where is the nucleus located for the abducens nerve?
Pons
What structure is innervated by the abducens nerve?
Lateral rectus muscles
What type of disorder is internuclear opthalmoplegia?
Disorder of conjugate gaze- failure of adduction of affected eye with nystagmus on lateral gaze in contralateral eye
Describe internuclear opthalmoplegia?
- Unilateral or bilateral
- Results from lesion of medial longitudinal fasiculus (connects III & VI nerve nuclei)
- Commonly seen in multiple sclerosis
What are the 4 clincial features of Horner’s syndrome?
- Miosis
- Ptosis
- Apparent enopthalmos
- Anhidrosis
What does horner’s syndrome result from?
Ipsilateral disruption of cervical / thoracic sympathetic chain
List 8 causes of Horner’s syndrome?
- Congenital
- Brainstem stroke
- Cluster headache
- Apical lung tumour
- Multiple sclerosis
- Carotid artery dissection
- Cervical rib
- Syringomyelia