the eye and orbit Flashcards
bones of the orbit
1) frontal
2) zygomatic
- zygomaticofacial foramen
- arteries from the eye come out
3) maxilla
4) lacrimal
5) ethmoid
- ethmoidal foramina (anterior and posterior)
6) sphenoid
7) palatine
relationships around the orbit
1) frontal lobe sits on top of the orbits
2) floor is the maxilla covering the maxillary sinus infections
3) ethmoid with ethmoidal sinuses
contents of the orbit
1) bulbous oculi (eye)
2) seven extraocular muscles
3) fat
4) lacrimal gland
5 )CN II, III, IV, V (V1), and VI
6) arteries and veins
periorbita and dural sheath of the optic nerve
1) periorbita wraps the eye
- tough and peels off
2) orbital septa
- fibrous piece
3) dura on the optic nerve
surface anatomy
1) palpebrae
2) palpebral commissures
3) superior inferior papillae and puctum
- lump on the top with hole
4) plica semilunaris
- vestigial membrane (pink and clear)
- remnant of nictitating membrane
5) lacus lacrimalis
- lake of tears
- caruncle: fleshy gland tissue in the corner
6) cornea with iris and pupil
7) scleras
surface anatomy internal
1) conjunctiva
- mucus membrane covering the eye and eyelids
- stratified columnar epithelium with goblet cells
- continuous membrane (palpebral and transparent bulbar portion)
- tarsal glands
2) conjunctival sac
- loop in the conjunctiva that transitions between the palpebral and bulbar portions
orbital septum and tarsal plates
1) muscles
- orbicularis oculi
- levator palpebrae superioris
- superior tarsal (smooth muscle, sympathetic, ptosis)
2) tarsal plate
- dense CT
3) tarsal glands
- sebaceous glands
- oily substance
4) GSA innervation
- upper eyelid CN V1
- lower eyelid CN V2
lacrimal gland
1) bilobed serous gland
2) superolateral margin of orbit
3) secret fluid to moisten eyeball
4) drainage
- via duct system into nasal cavity
lacrimal drainage
1) gland => lacus lacrimalis => punctum => lacrimal canaliculi => lacrimal sac => nasolacrimal duct => nasal cavity (lateral to inferior nasal conchae)
fluid that moistens the eye comprises secretions from the
1) tarsal glands
2) lacrimal glands
3) conjunctival epithelium
coats of the bulbous oculi
1) three layers
- fibrous, vascular, and retinal
fibrous coat
1) external layer and composes sclera and cornea
2) sclera forms posterior 5/6
vascular layer
1) pigmented
2) choroid 5/6 posterior
3) ciliary body comprises mostly the ciliary muscle and process
- suspensory ligaments between ciliary body and lens
4) iris extends from ciliary body
- pigmented diapragm
- opening is the pupil
5) anterior and posterior compartments with aqueous humor
ciliary muscles
1) contraction looses suspensory ligament
- postsynaptic parasympathetic fibers from ciliary ganglion
- presynaptic carried with CN III
constrictor pupillae muscle
1) circular fibers, decrease pupil size
- POSTsynaptic PARAsympathetic fibers from ciliary ganglion
- presynaptic carried with CN III
dilator pupillae muscle
1) radiating fibers
- dilates pupil
- POSTsynaptic SYMPATHETIC fibers from superior cervical ganglion
- running through the ciliary ganglion
extra ocular muscles of the orbit
1) levator palpebrae superioris
2) superior rectus, medial rectus, inferior rectus, lateral rectus
3) superior oblique, inferior oblique,
arterial supply opthalmic artery (6 branches)
1) lacrimal artery (2 main branches)
- lacrimal branch
- zygomatic branch
2) posterior ciliary arteries
3) supraorbital artery
4) anterior and posterior ethmoidal arteries
5) dorsal nasal artery
6) supratrochlear artery
lacrimal branch
to gland superiorlateral eye
- goes UP
zygomatic branch
- zygomaticofacial a.
- zygomaticotemporal a.
- goes DOWN
posterior ciliary arteries
- one becomes the central artery of the retina
posterior and anterior ethmoidal arteries
1) to ethmoidal air cells
2) anterior branch becomes external nasal artery
dorsal nasal artery
1) medial angle of upper eye lid
supratrochlear artery
1) supraorbital / tochlear notch
superficial branches of the opthalmic arteries
1) supraorbital, supratrochlear, dorsal nasal, external nasal, zygomaticofacial, zygomaticotemporal
venous drainage
1) superior ophthalmic vein
2) communicates with facial vein anteriorly
3) communicates with cavernous sinus posteriorly
special sensory and motor nerves
1) optic CNII
2) trochlear CN IV
- superior oblique muscle
- superior orbital fissure
3) abducens CN VI
- superior orbital fissure to the lateral rectus muscle
4) general somatic efferent ( GSE)
- oculomotor CN III
- all the other ones
- carries parasympathetics to ciliary ganglion
GSA
1) ophthalmic division of V1
- via superior orbital fissure
- 3 branches: lacrimal, frontal, nasociliary
lacrimal nerve
1) sensory to lacrimal gland
- lateral aspect of upper lid
frontal nerve
1) supraorbital and supratrochlear
nasociliary nerve part 1
1) ganglionic branches to ciliary ganglion then short ciliary nerves
2) long ciliary branches: sensory to eye and cornea
nasociliary nerve part 2
1) posterior ethmoidal
2) anterior ethmoidal
- external nasal nerve
3) infratrochlear nerve
ciliary ganglion
1) receives general sensory fibers from CN V1
2) sympathetic fibers extending from superior cervical ganglion via plexus on internal carotid and ophthalmic arteries
3) parasympathetic fibers from oculomotor nerve
- only one synapse in ganglion
short ciliary nerves
1) mixed nerves
2) sensory from eye
3) sympathetic to dilator pupillae muscles
4) parasympathetic to constrictor pupillae and ciliary muscles
lacrimal gland innervation
1) general sensory via lacrimal nerve CN V1
2) parasympathetics
- preganglionic fibers from CN VII at pterygopalatine ganglion
- postganglionic fibers from pterygopalatine ganglion via zygomaticotemporal nerve (V2) then via communicating branch to lacrimal nerve (V1)
abductors
1) superior oblique
2) inferior oblique
3) lateral rectus
adductors
1) medial rectus
2) superior rectus
3) inferior rectus
depressors
1) superior oblique
2) inferior rectus
elevators
1) inferior oblique
2) superior rectus
lateral rotators
1) inferior oblique inferior rectus
medial rotators
1) superior oblique superior rectus
