Section 3: Flashcards
can cranial nerve dysfunction cause monocular diplopia?
no
what are some differentials if the patient has monocular diplopia
uncorrected astigmatism, cornea, cataract, Srx
if patient has horizontal diplopia, what muscles do you think are affected?
lateral or medial rectus
if patient has vertical diplopia, what muscles do you think are affected?
SO, IO, SR, or IR
what muscles may be affected if the patient has horizontal diplopia worse at far
lateral rectus
what muscles may be affected if the patient has horizontal diplopia worse at near
medial rectus
what muscles may be affected if the patient has vertical diplopia worse at far
IR or SR
what muscles may be affected if the patient has vertical diplopia worse at near
IO or SO
if patient moves chin up or down, their problem is likely
vertical muscle problem
if patient has a head turn, their problem is likely
horizontal muscle problem
if patient has a head tilt, their problem is likely
torsional component
where else does fibers from CN III travel to
iris sphincter and levator
what innervates the Obicularis
CN VII
oculosympathetic innervation goes to:
Mueller’s muscle/ Dilator
12 diagnostic tests you should run
- pinhole (if monocular diplopia)
- keratometry (if monocular diplopia)
- pupils
- cover test
- parks 3 step
- versions/ductions
- red lens/ maddox rod in 9 fields of gaze
- refraction
- phorometry
- saccades/OKN
- cranial nerve evaluation
- ocular health evaluation
most common ocular motor nerve palsies are
- abducens, VI (44-57%)
- trochlear, IV (21-28%)
- oculomotor, III (15-17%)
- multiple (5-13%)
origin of oculomotor nerve
oculomotor nuclei and edinger westphal nuclei
only nucleus with sub nuclei
superior branch of oculomotor nerve has the
SR, Levator
inferior branch of the oculomotor nerve has the
IO, IR, MR
what are the parasympathetic fibers of the oculomotor nerve
iris sphincter, ciliary muscle
what are 4 signs of a complete CN III palsy
- ptosis
- mydriasis
- exotropia/ hypotropia
- pain (retro-orbital and peri-orbital)
what are some differential diagnoses for 3rd nerve palsy
- myasthenia gravis
- thyroid eye disease
- CPEO- chronic progressive external ophthalmoplegia
- midbrain lesion
- orbital fracture
- Brown’s syndrome
where are some proposed areas of injury for CN III palsies
- exit from brainstem
- herniation against tectorial region
- superior orbital fissure
what are some important aspects of congenital III nerve palsy
- formed from absence or incomplete development of the III nerve nucleus or nerve
- may have amblyopia
- rare in comparison to acquired III nerve palsy
- aberrant regeneration
