Cranial nerve examination Flashcards
Recall 2 causes of pupil asymmetry that you may see on cranial nerve examination
Horner’s: causes small reactive pupil
CN III palsy: causes large pupil
How far away from a Snellen chart should the patient stand for visual acuity testing?
6 metres
In what pathology is RAPD seen?
Optic neuritis (eg MS)
Recall 3 causes of ptosis
CNIII pathology
Horner’s
Myasthaenia gravis
Name the 3 branches of the trigeminal nerve
Ophthalmic
Maxillary
Mandibular
Which branch of the trigeminal nerve has a motor element, and what does it control?
Mandibular
Muscles of mastication
Which cranial nerve forms the afferent and efferent limbs of the corneal reflex?
Afferent = CNV Efferent = CNVII
Which portion of the tongue gets its sensory supply (taste) from the facial nerve?
Anterior two thirds
How can facial nerve palsy affect hearing?
Supplies stapedius muscle. If this is damaged –> hyperacusis
How can the vestibular function of CNVIII be tested?
Turning test - Ask the patient to march on the spot with eyes closed and arms outstretched. If there is a lesion, they will turn towards it.
Recall the direction of deviation of the tongue and the uvula when there is a lesion
Tongue: towards lesion (CNXII)
Uvula: away from lesion (CNX)
How can the olfactory nerve be tested?
Ask them to smell coffee/ nail varnish/ vanilla essence
Must test BOTH nostrils
How can the sensory portion of the optic nerve be tested?
- Assess acuity with Snellen chart (or ask them to read time off clock behind you)
- Assess colour vision using Ishihara plates
- Assess for neglect/ inattention by holding your hands out in periphery of vision and wiggling fields on each side and then both at same time and asking pt which side you are wiggling fingers on
- Assess fields - nb. these are CIRCULAR so you need to start behing the patient and come forwards as well as up and down
How can the motor function of the optic nerve be tested?
Nil
How can the optic nerve reflexes be tested?
- Direct and consensual light reflexes - shine pen torch into eye and assess for constriction of ipsilateral and then contralateral pupil
- Swinging light test (more info on a different card)
- Test accommodation reflex (normal –> BL convergeance and constriction)