41B Oculomotor Flashcards
How is paralytic (non-comitant) strabismus characterized?
variable angles of deviation in different fields of gaze
Etiology of paralytic (non-comitant) strabismus?
Weakness of one or more extraocular muscles
Age typically affected by paralytic (non-comitant) strabismus?
adults
Vision abn caused by paralytic (non-comitant) strabismus?
diplopia in the direction of gaze where affected muscle is supposed to be working the hardest
Age typically affected by non-paralytic (comitant) strabismus?
childhood
**no musc weakness
Vision abn caused by non-paralytic (comitant) strabismus?
No diplopia – brain suppresses one of the images leading to amblyopia in that eye
How is non-paralytic (comitant) strabismus characterized?
angle of deviation is similar in all fields of gaze
A patient with a tropia has:
A patient with a phoria has:
deviation of the visual axes present at all times
deviation of the visual axes only when fusion is disrupted
Cause of horizontal diplopia?
weak LR or MR
Cause of vertical diplopia?
weak SO, IO, SR, IR
CN III nerve palsy + HA =
aneurysm at the junction of the posterior communicating and posterior cerebral arteries
CRANIAL NERVE III palsy with normal pupillary responses usually indicates:
microvascular cause
CRANIAL NERVE III palsy with normal pupillary responses usually occurs in…
middle-age or older patient with Dm or HTN
Symptoms of CN VI palsy?
- loss of ABduction (LR) = esotropia
- diplopia incr on gaze to side of lesion
Causes of CN VI palsy?
incr ICO trauma stroke tumor microvasc
Symptoms of CN IV palsy?
- weakness or paralysis of SO
- vertical diplopia
- SPONTANEOUS HEAD TILT toward the side OPPOSITE the weakened muscle
Causes of CN IV palsy?
trauma
microvasc
congenital
