Cranial Nerve Lesions Flashcards
Which two extraocular muscle are NOT innervated by the oculomotor nerve
Lateral rectus
Superior oblique
What muscle is responsible for lifting the upper eyelid and what nerve innervates it
- Levator palpebrae
- Oculomotor
How does a 3rd nerve palsy present
- Ptosis and squint
- Fixed dilated, non-reactive pupil
- Eye pulled down and out
- Diplopia
How does a 3rd nerve palsy cause a dilated, non-reactive pupil
The oculomotor nerve carries parasympathetic fibres that intervate the circular muscles of the iris
What does a 3rd nerve palsy that spares the pupil suggest (2)
Microvascular cause
* DM
* HTN
* Ischaemia
What extraocular muscle does the trochlear nerve supply
Superior oblique
What are 3 functions of the superior obliques
- Primary: Intorsion
- Depression
- Abduction
How does a trochlear nerve palsy present
- Affected eye deviates upwards and slightly out
- Affected eye elevates further as it moves medially
- Vertical diplopia
What extraocular muscle does the abducens nerve supply
Lateral rectus
How does a 6th nerve palsy present
- Affected eye turns inwards at primary position
- Unable to abduct affected eye but can adduct
*Horziontal diplopia when looking far away or in the direction of the affected eye
How may patients with a 4th nerve palsy compensate for vertical diplopia
Head tilt to better align the eyes and reduce the diplopia
3 ways a trigeminal nerve palsy may present
- Weakness/paralysis of chewing muscles
- Increased pain
- Loss of corneal reflex
3 ways a facial nerve palsy may present
- Ipsilateral weakness/paralysis of the muscles of facial expression
- Facial droop
- Loss of taste
What does the facial nerve supply sensory innervation to
Anterior 2/3 of the tongue
3 ways a vestibulocochlear palsy may present
- Hearing loss
- Tinnitus
- Loss of balance
