Clinical Anatomy- The Eye and raised ICP

Question 1

what is the ‘sunset sign’ often seen in?

Answer 1

hydrocephalus

Question 2

what is the ‘sunset sign’

Answer 2

failure of upward looking

Question 3

why does a raised ICP have a different affect on babys than adults?

Answer 3

their cranial cavity is still not fully ossified so it is more flexible and can expand to accomodate the swelling

Question 4

what does a raised ICP lead to?

Answer 4

damage to tissues, shifts tissues, constriction of blood vessels and nerves

Question 5

what type of visual problems can people with raised ICP present with?

Answer 5

transient blurred vision, double vision, loss of vision

Question 6

what can be seen clinically in the eyes in raised ICP?

Answer 6

papilloedema (swelling of optic disc)

pupillary changes

Question 7

what pupillary change is an early sign of raised ICP?

Answer 7

dilated pupil

Question 8

why are the optic nerves actually more like ‘extensions of the brain’?

Answer 8

they are covered in meninges

Question 9

what are the 3 types of meninges?

Answer 9

dura, arachnoid, pia

Question 10

what is the space between the arachnoid and the pia known as?

Answer 10

sub-arachnoid space

Question 11

what is the sub-arachnoid space filled with?

Answer 11

CSF

Question 12

what else does the menignes cover other than the brain?

Answer 12

spinal cord

Question 13

what encloses the dural venous sinuses?

Answer 13

dura mater

Question 14

what is the sensory supply to the dura mater?

Answer 14

CN V

Question 15

what layer of meninges is described as ‘spidery’?

Answer 15

arachnoid mater

Question 16

what is the pia adherent to?

Answer 16

the brain and vessels and nerves entering or leaving

Question 17

what are the 2 layers of the dura mater and what sits between the 2 layers?

Answer 17

endosteal layer and meningeal layer- encloses dural venous sinuses

Question 18

where is CSF produced in the brain?

Answer 18

choroid plexus of the ventricles

Question 19

how is the CSF reabsorbed into the dural venous sinuses?

Answer 19

via arachnoid granulations

Question 20

how are samples of CSF obtained?

Answer 20

lumbar puncture

Question 21

where is the choroid plexus located?

Answer 21

in the lateral and third ventricles

Question 22

Once CSF is produced where does it go?

Answer 22

the right and left lateral ventricles

Question 23

After the right and left lateral ventricles, where does the CSF go?

Answer 23

the midline - the 3rd ventricle

Question 24

how does CSF from the 3rd ventricle move to the 4th ventricle?

Answer 24

via the cerebral aqueduct

Question 25

once CSF is at the 4th ventricle where does most of it go?

Answer 25

in subarachnoid space

Question 26

where does the small amount of CSF that doesnt go to the brain go?

Answer 26

central canal of the spinal cord

Question 27

how is CSF reabsorbed?

Answer 27

from the subarachnoid space via the arachnoid granulations into dural venous sinuses

Question 28

what does raised ICP compress in relation to the eye?

Answer 28

optic nerve and central artery and vein

Question 29

how does the disc appear in papilloedema?

Answer 29

bulging or swollen and blurred with a less sharp disc margin

Question 30

if the occulomotor nerve is compressed, what 2 innervations to the eye are paralysed?

Answer 30

somatic motor of 4 extra-ocular muscles and eyelid and parasympathetic innervation of the sphincter of the pupil

Question 31

if the oculomotor nerve is damaged, what position will the eyeball be in?

Answer 31

down and out

Question 32

what notch can part of the brain herniate though when there is raised ICP and what nerve does the compress/stretch?

Answer 32

medial temporal lobe herniates though tentorial notch and can compress/stretch oculomotor nerve

Question 33

folds of dura mater in the cranial cavity creates a septa, what does is divide the brain into?

Answer 33

falx cerebri and tentorium cerebelli

Question 34

what is different about the course of the trochlear nerve compared to all over CNs?

Answer 34

comes out and the back of the brain (not anteriorly) and then has to come back round

Question 35

what muscle of the eye loses its innervation when CN IV is damaged?

Answer 35

superior oblique

Question 36

in what position will the eye sit if trochlear nerve is damaged?

Answer 36

in and up

Question 37

in what direction can the eye not look when trochlear nerve is damaged?

Answer 37

inferomedially - down and in

Question 38

is it common or rare that the trochlear nerve is affected on its own?

Answer 38

rare

Question 39

what nerve must be damaged if there is paralysis of the lateral rectus muscle?

Answer 39

abducent nerve

Question 40

what position does the eye sit in if the abducent nerve is damaged?

Answer 40

medially deviated