the eye and raised ICP anatomy Flashcards
(33 cards)
CNV (trigeminal nerve)
Pia
S2
4th ventricle
choroid plexus
True or False
Most patients with ICP will report visual problems
true
65-75% of patients with ICP will report visual problems
why is a raised ICP dangerous?
-as it can cause damage to tissues, shifts in tissues, herniation and constriction to blood vessels
what must exist in equilibrium with echother in the cranial cavity?
- brain
- blood
- CSF
This is the Monroe-kellie hypothesis so if one increases another must decrease
what are optic nerves surrounded by?
-cranial meninges
dura on outside, arachnoid in middle and Pia which completely sits closest to optic nerve
what is the space between the arachnoid and Pia called?
sub-arachnoid space (filled with cerebrospinal fluid)
what is the subarachnoid space filled with?
cerebrospinal fluid
why does raised ICP affect vision?
- raised ICP will compress the optic nerve as the is cerebrospinal fluid in the sub arachnoid space of the nerve
- it will also compress the nerve and artery
what are meninges?
-the protective coverings of the brain and spinal cord
what are the levels of meninges?
- dura
- arachnoid
- subarachnoid space
- pia
what are dural septa?
-folds of dura mater
what does the tentorium cerebelli do?
-divides the cerebellum
EDIT
what does the tentorium cerebelli do?
-divides the cerebellum
EDIT
where does the brain stem pass in relation to the tentorium cerebelli?
-tentorium notch (brain can herniate through the tentorium notch)
when may raised ICP compress/stretch the oculomotor nerve?
-if the medial temporal lobe herniates through tectorial notch
what effect does the medial temporal lobe herniating through the tentorial notch have on the eye ?
- paralyis of somatic nerve intervention (4 extra ocular muscles and eyelid)
- paralysis of parasympathetic innervation sphincter of pupil
- lose/slowness of pupillary light reflex, dilated pupil, ptosis, eye turned inferolaterally ‘down and out’
what occurs if there is damage to trochlear nerve?
- paralysis of superior oblique muscle
- inferior oblique is unopposed so eye cannot move inferomedially and there will be diplopia when looking down
how may raised intracranial pressure affect the adbducent nerve?
-there may be damage by it stretching
- there will be paralysis of lateral rectus muscle
- the eye cannot move laterally in horizontal plane (medial deviation of the eye)
what abnormal anatomy can you see?
- lack of symmetry (right orbital floor fracture and herniation)
- fluid in the sinus
baby scratches mums eye, she feels extreme pain in the eye
-why is this?
- CNV1 picks up sensation of pain
- extremely painful as it is very densely innervated
