Disorders of Cranial Nerves Flashcards
(45 cards)
What are the Functions of the Cranial Nerves?
- Special” senses
- “Ordinary” sensation
- Control of muscle activity
- Autonomic functions
What are the special sense?
Olfaction (I)
Vision (II)
Taste (VII, IX and X)
Hearing - and balance (VIII)
What is responsible for ordinary sensation?
Mainly the Vth (trigeminal nerve)
The ear from the VIIth (facial) and IXth (glossopharyneal) nerves
What is in control of msucle activity?
Eye muscles – III (oculomotor), IV (trochlear) and VI (abducence) (LR6,SO4, rest 3)
Muscles of mastication – V (trigeminal)
Muscles of facial expression – VII (facial)
Muscles of larynx and pharynx – mainly X (vagus)
Sternomastoid and trapezius muscles - XI (accessory)
What are the autonomic functions
(all parasympathetic) and what is respobisble for them?
Pupillary constriction – III (oculomotor)
Lacrimation – VII (facial)
Salivation – submandibular and sublingual glands – VII (facial)
Salivation – parotid gland - IX (glossopharyngeal)
Vagal (X) input to organs in thorax and abdomen
What is used to test CN I - Olfactory?
smell – unilateral or bilateral loss
What is used to test CN II – Optic?
visual acuity
visual fields
pupillary reactions
fundoscopy
colour vision
What dow e test in CN III, IV and VI – oculomotor, trochlear and abducence?
any evidence of ptosis?
pupil of equal size?
pupillary reactions
eye movements – vertical and horizontal
What do we for for in regards to CN V – Trigeminal?
sensation in the ophthalmic, maxillary and mandibular divisions
power in the muscles of mastication
corneal reflex
•aw jerk
What do we test for in CN VII – Facial?
Muscles of facial expression
Corneal reflex
Taste
What do we test for in CN VIII – Vestibulocochlear nerve?
Hearing using Rinne’s and Weber’s tests
Vestibular function using Dix-Hallpike manoevre and Untenberger’s test
(untenbergers test – close eyes and march on spot and will start to turn to side that is dyfunctioning and need to go to ENT clinic)
What do we test for in CN IX (glossopharyngeal) and CN X (vagal)?
movement of the palate
gag reflex
quality of speech
quality of cough
WHat do we test for in CN XI – Accessory nerve?
Head turning and shoulder shrugging - sternomastoid and trapezius function
How is CN XII – Hypoglossal nerve tested?
Appearance, movement and power of tongue
What cranial nerves are responsible for:
Pupillary light reaction
afferent – II ; efferent – III
What cranial nerves are responsible for:
Corneal reflex
afferent – V ; efferent – VII
What cranial nerves are responsible for:
jaw jerk
afferent and efferent – V
What cranial nerves are responsible for:
gag reflex
afferent – IX ; efferent - X
III and IV (Oculomotor and Trochlear) nuclei lie in the ________
MID-BRAIN
V, VI AND VII (Trigeminal, Abducent and Facial) lie in the ______
PONS
VIII (Vestibulocochlear) lie at the __________ junction
PONTOMEDULLARY
IX, X XI and XII (Glossopharyngeal, Vagus, Accessory and Hypoglossal ) lie in the ________
MEDULLA
What may be some Combinations of Cranial Nerve Signs?
Bilateral III - midbrain
III +IV+VI - superior orbital fissure
VI +VII -pons
V + VIII - cerebellopontine angle
Unusual combinations - ?chronic or malignant meningitis
Pure motor signs - ?myasthenia gravis - affects neuromuscular junction
What different ways can cranial nerves be damaged?
within the brain - e.g. by ischaemia, tumour
crossing the sub-arachnoid space - e.g by meningitis
outside the skull e.g. by base of skull tumours arising in nasopharynx
