Flashcards in Week 4 Deck (59)
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1
Components of cranial nerves
General sensory axons
Special sensory axons
Motor axons
Autonomic axons
2
What part of the nervous system are the cranial nerves a part of
Peripheral nervous system
3
How do cranial nerves differ from spinal nerves
Arise at irregular intervals from the CNS
4
What's the brainstem
Connects the brain to the spinal cord and has 3 parts:
Midbrain
Pons
Medulla
5
What are cranial nerve nuclei and where are the majority
Collections of cell bodies of nerve fibres which make up the cranial nerves
In the brainstem
6
Describe the route, fibres present and function of the olfactory nerve
Route - cell bodies in olfactory nasal mucosa, pass through foramina in cribriform plate, enter olfactory bulb (in contact with frontal lobe of cerebral hemispheres)
Fibres - special sensory
Function - smell
7
How would you test olfactory nerve function
Smelling salts - one nostril at a time
8
How do the first 2 cranial nerves differ from the rest
Anterior extensions of forebrain
9
What is anosmia and the causes in order of most common
Loss of sense of smell
Causes:
URTI
Head injury that fractures the cribriform plate
10
Describe the route, fibres present and function of the olfactory nerve
Route - passes through the optic canal from the retina and crosses over to form the optic chiasm near the pituitary. It then becomes the optic tract.
Fibres - special sensory
Function - vision
11
How would you test the optic nerve
Visual tests and look at pupils
One eye at a time
12
What can cause lesions of the optic nerve and therefore vision loss
Optic neuritis
Pituitary tumours
Stroke
Carotid aneurysm
13
How can the optic nerve be viewed
Fundoscopy
14
Describe the route, fibres present and function of the oculomotor nerve
Route - arises from midbrain, runs in cavernous sinus, goes through the superior orbital fissure
Fibres - Motor and parasympathetic autonomic
Function - motor innervation to (sup, med, inf) recti, inferior oblique and levator palpebrae superioris; constriction of pupil
15
How can the oculomotor nerve be tested
Eye movements
Inspect eyelids and pupils
Pupillary light reflex
16
What structures are in the cavernous sinus
Internal carotid arteries
Oculomotor nerve
Trochlear nerve
Ophthalmic nerve
Maxillary nerve
Abducent nerve
17
Causes of oculomotor nerve lesions
Raised intracranial pressure
Aneurysms
Cavernous sinus thrombosis - clot in cavernous sinus usually from infection spread from skull/face
Diabetes (pupil sparing)
18
What symptoms arise with oculomotor nerve lesions
Diplopia - double vision
Ptosis - dropping eyelid
Dilated pupil
19
Describe the route, fibres present and function of the trochlear nerve
Route - longest route because it arises from the posterior midbrain. Enters the orbit through the superior orbital fissure
Fibres - motor
Function - motor innervation of superior oblique
20
How can the trochlear nerve be tested
Eye movements
21
Causes of trochlear nerve damage
Head injury
Congenital palsies
22
Symptoms of trochlear nerve damage
Diplopia worse on downward gaze
23
Describe the fibres present and function of the trigeminal nerve
Fibres - Motor, autonomic and sensory
Function - mastication and sensory innervation to most of the face
24
Branches of the trigeminal nerve and where they exit the skull
Ophthalmic - superior orbital fissure
Maxillary - foramen rotundum
Mandibular - foramen ovale
25
What does the ophthalmic nerve supply
Frontonasal prominence
Scalp
Forehead
Orbit
External nose
Lacrimal gland
(Does corneal reflex)
26
What does the maxillary nerve supply
Skin around the upper jaw
Glands of the nose
27
What does the mandibular nerve supply
Motor - muscles of mastication
Sensory - side of the head, cheeks, anterior 2/3 tongue, chin, lower lip
Autonomic - parotid gland
28
How do you test the trigeminal nerve
Test corneal reflex - involuntary blinking by touching the cornea
29
How can the trigeminal nerve be damaged
Herpes zoster infection
Trigeminal neuralgia
Trauma
30
