Cranial Nerve IV trochlear nerve Flashcards
trochlear nerve (CN IV) is a somatic motor nerve that innervates _____ only?
SO muscle only
the trochlear nerve is the only CN nerve with _____ exit & to project 100% ___?
dorsal exit & project 100% contralaterally
dorsal: Relating to the back or posterior of a structure.
Contralateral means?
Of or pertaining to the other side
because the trochlear nerve projects contralaterally a lesion___?
of the trochlear nucleus will affect the SO on the contralateral side
which nerves pass thru the oculomotor nerve?
SNIA see no intent at all
- superior division of oculomotor nerve
- nasociliary nerve
- Abducent nerve
-inferior division of oculomotor nerve
which nerves pass outside of the oculomotor foramen?
LFT live freely to
- lacrimal nerve
- frontal nerve
- trochlear nerve
lesion of CN IV (4) can lead to
extrusion, elevation, adduction (because it affects the SO which performs the opposite actions)
Head tilts ____ from affected orbit to minimize diplopia
Head tilts away from affected orbit to minimize diplopia (rule for palsy of EOMs with secondary action of intorsion
trochlear nerve palsy causes?
-Congenital: May present with double vision due to decompensation
-Traumatic and ischemic (vascular) etiologies are most common causes
-Other causes include: tumors, infarction, demyelination, cavernous sinus thrombosis, ICA aneurysm, cavernous sinus infection, meningitis
Abducens nerve (CN VI) 6 is a somatic motor nerve which innervates___?
LR muscle only
where is Abducens nerve (CN VI) located?
caudal pons
Abducens nerve (CN VI) emerges from____?
ventral aspect of
brainstem near pontomedullary junction
Abducens Nerve (CN VI) Palsy
-vasculopathic (ischemic), traumatic and idiopathic causes are the most common
