anatomy 2 Flashcards
4 parasympathetic ganglia of head + neck
ciliary ganglion
pterygopalatine ganglion
otic ganglion
submandibular
synapse that occurs in ciliary ganglion
presynaptic parasympathetic fibres from inferior division of CN III
–>
postsynaptic short ciliary nerve
pathway of oculomotor (CNIII)
skull exit?
connects with CNS at junction of midbrain + pons
passes through cavernous sinus
exits via superior orbital fissure
splits into superior + inferior
where do the rectus muscles of the eye originate from? where do they insert into?
common tendinous ring
all insert into sclera
where do the superior + inferior oblique muscles of the eye originate from respectively? where do they insert into?
superior = sphenoid bone
inferior = orbital plate of maxilla
BOTH insert into sclera
where does levator palpebrae superioris originate from? where does it insert into?
originates from lesser wing of sphenoid
inserts onto skin + tarus of superior eyelid
innervation of extraocular muscles
LR6 SO4 AO3
lateral rectus = CNVI abducent
superior oblique = CNIV trochlear
all others = CNIII oculomotor
which part of the orbit is most prone to blowout fractures?
inferior (orbital flooe) + medial wall
fractures commonly occur at sutures forming orbital rim
name the muscle of the eyelid and its innervation
orbicularis oculi divided into - orbital + palpebral parts
CNVII
which muscle is responsible for tightly squeezing your eyes shut?
orbital part of orbicularis oculi
which muscle is responsible for gently closing your eyes shut?
palpebral part of orbicularis oculi
role of superior tarus muscle
open eye really wide
sympathetic innervation
role of tarsal gland
secretes lipids prevents tears (lacrimal fluid) overflowing (when being produced in normal amounts)
when does lacrimal fluid drain to?
inferior meatus via lacrimal puncta
location of lacrimal gland
superolaterally of orbit
parasympathetic (CN VII)
layers of the eye
outer = fibrous (sclera + cornea)
middle = uvea (vascular layer) -> iris, ciliary body, coroid
inner = retina (photosensitive)
where do all the rectus muscles of the eye originate from? where do they insert into?
all originate = common tendinous ring
all insert into sclera
where do the oblique muscles of the eye originate from? where do they insert into?
originates
Superior oblique = Sphenoid bone (S-S)
inferior oblique = orbital plate of maxilla
both insert into sclera
where does the levator palpebrae superioris originate from? where does it insert into?
originates - lesser wing of sphenoid (LPS-LWS)
inserts - skin + tarus of superior eyelid
how many extraocular muscles are there?
7 skeletal muscles
4 rectus
2 oblique
1 levator palpebrae superioris
extraocular muscles responsible for pure elevation of eye?
superior rectus + inferior oblique
synergistically to elevate eyes but antagonists (working against each other) as rotators
extraocular muscles responsible for pure depression?
superior oblique + inferior rectus
synergistically depress eyes
but antagonists as aDductors/aBductors
where do parasympathetic ganglia tend to be located compared to sympathetic?
parasympathetic - usually near organ its acting on
sympathetic - ganglia usually in spinal trunk
where/what is the limbus?
corneoscleral junction
3 parts of the uvea from anterior to posterior
iris
ciliary body
choroid - nutrition + gas exchange
function of ciliary body
- controls iris, shape of lens + secretion of aqueous humour
common location of “floater”
vitreous body
circulation of aqueous
- ciliary processes in ciliary body secrete aqueous
- aqueous circulates within pos chamber, nourishes lens
- passes through pupil to ant chamber, nourishes cornea
- aqueous absorbed into scleral venous sinus = canal of Schlemm at iridocorneal angle
angle involved in open-angle + closed-angle glaucoma
iridocorneal angle
pathways of internal carotid artery to ophthalmic artery
passes through carotid foramen then through cavernous sinus
–> as passes through cavernous sinus ophthalmis artery branches off
which artery pierces the optic nerve?
central artery of retina = end artery, only artery that supplies retina
where is the danger triangle of the face? why is it dangerous?
upper lip, nose, to between brows
method of spread of infection
what is the fundus? what does this incluse?
posterior area where light is focused
- optic disc
- macula
- fovea
optic disc
point of CN II formation
only point of entry/exit for blood vessels + axons of CN II
blind spot
where is the greatest density of cones?
macula
fovea
centre of the macula
depression, 1.5mm diameter
area of most acute vision
why is the optic disc the “blind spot”?
there are no photoreceptors in the optic disc
where do the retinal veins + arteries lie in respect to the retina?
anterior
interruption of flow to central artery vs retinal artery branch
branch = loss of an area of visual field corresponding to the area of ischaemia
central = monocular blindness
movement of vertical axis of eye
abduction / adduction
movement of transverse axis
elevation / depression
movement of anteroposterior axis
intorsion/extorsion
