Anatomy Of Eye Flashcards
With regards orbital margin, superior formed of…..showing…., med….,lat….., inferiorly…..
Frontal b, supraorbital formaen
Frontal and maxilla
Frontal and zygomatic
Zygomatic and maxilla
Roof of orbit is formed of…..,while floor is formed of…….
R,Orbital plate of frontal bone
Lesser wing of sphenoid
F, maxilla, zygoma, orbital plate of palatine bone
The medial wall of orbit is formed of….while lateral wall is formed of…..
M, maxilla, lacrimal bone, orbital plate of ethmoid, body of sphenoid
L, frontal process of zygomatic, greater wing of sphenoid
Enumerate conents of superior orbital fissure in different compartments
Lat, lacrimal, frontal, trochlear, superior ophthalmic vein
Mid, superior division of III, nasocillariry, inf division of III, abducent
Med, inferior ophthalmic vein, sympathetic nerves from plexus around ICA
Med and mid lie WITHIN tendionous ring
Mentuon conetnets of inferior orbital fissure
- Continuation of maxillary n (or inflraorbital n)
- Zygomatic nerve
- Orbital branches of pterygopalatine ganglion
- Infraorbital vessels
- Communication between inf ophthalmic v and pterygoid plexus of veins
All contents of orbit are found inside periosteum except…..
Infraorbital nerve and vessels
Zygomatic nerve
Describe extension of orbital periosteum
Posteriorly cont with dura mater and sheath of optic n, ant cont with periosteum and thickened
Sends flap-like curtains into eyelids called orbital septum
Ddescribe extension of bulbar fascia
Extends from optic nerve to limbus
Enumerate expansions of bulbar fascia
- Tubular sheath around extraocular muscles
- Medial and lat check ligents from sheaths of med and lat recti respectively
- Suspensory ligament (hammock)
Describe origin and insertion of recti muscles
O, all origitante from common tendinous ring which is laterally attached to bony projection in lower border of superior orbital fissure, and medially attached to optic canal
I, inserted in front of the equator of the eye ball posterior to the limbus
Describe attachments of SO muscle
O, roof of orbit (lesser wing of sphenoid) runs in medial wall of orbit then passes through fibro-cartiagenous pulley in trochear fossa and changes its direction to pass lat and back below SR
INS, into sclera behind equator of the eyeball
Describe origin and ins of IO
O, floor of orbit (maxilla lat to lacrimal groove passes lat anf back below IR
INS, into sclera behind equator of the eyeball
Describe origin and ins of LPS
O, orbital surface of lesser wing of sphenoid antero-superior to optic canal
I, flat tendon splits into lamella inserted into: skin of upper eyelid, superior tarsus (Muller muscle), superior fornix
Describe CN III supply of extra-occular msucles
Sup division, SR and LPS
Inf division IO, MR, IR
Mention extra-ocular muscles having the following action:
1. Adduction
2. Abduction
3. Intorsion
4. Extorsion
- MR, SR, IR
- LR, SO, IO
- SR, SO
- IR, IO
Mention the intraocular muscles and supply
Constrictor pupillae (parasympathetic)
Dilator pupilae (symp)
Ciliary muscle for accomodation of near vision (para)
Lacrimal gland has…..duct. Its arterial supply is……
12
Lacrimal branch of ophthalmic art
Describe the pathway of secretomotor fibers to lacrimal gland
Superior salivatory nucleus of facial nerve that gives preganglionic parasymp fibers as superficial greater petrosal nerve then n. to pterygoid canal then relays in pterygopalatine ganglion and gives postganglion para fibers in zygomatic n then zygomaticotemporal n the communicating branch to lacrimal n to lacrimal gland
Conjunctival sac is located between……
Bulbar and palpebral conjunctiva
The reflection of conjunctiva forms……
Superior and inferior fornices
The nasolacrimal duct opens into…..
Inferior meatus of nose
Enumerate parts of optic nerve and their length
Intra-orbital part, 25 mm
Intra-canalicular, 5 mm
Intra-cranial, 10 mm
Describe position of ciliary ganglion
Between optic nerve and tendon of lateral rectus
……pierce the optic nerve, while…..cross it
Central artery and vein of retina
Ophthalmic art, nasociliary n, superior ophthalmic vein
Describe arterial supply of optoc nerve
Intracranial part by superior hypophyseal art
Intracanalicular by branches of ophthalmic
Intraorbital by posterior ciliary arteries and central art of retina
Describe supplied areas of each of the following:
1. Lacrimal n
2. Supratrochlear n
3. Supraorbital n
- Lacrimal gland and lat part of upper lid
- Skin of forehead and upper eyelid
- Frontal air sinus and skin of forehead and scalp upto vertex
Enumerate branches of the nasociliary n
- Communicating branches to ciloary ganglion
- Long ciliary nerves to cornea, iris and ciliary body (sensory), motor to dilator pupilae (symp)
- Posterior ethmoidal passes throigh its foramen to supply ethmoidal and sphenoidal air sinuses
- Anterior ethmoidal passes through its foramen to cranial cavity then passes on side of crista gali to nasal cavity, leaves nasal cavity as extenal nasal n to skin of nose
- Infratrochlear n, supplies skin of upper eyelid and side of nose
CN III inside cranium passes between……(vessels).
Describe its autonomic role
Superior cerebellar and PCA
Nerve to IO carries parasympathetic fibers to constrictor pupilae and ciliaris muscles
Describe course of trochlear inside brain stem
Runs dorsally inside midbrain and decussates so each trochlear n supplies opposite SO muscle
Describe CP of damage of:
1. Oculomotor
2. Trochlear
3. Abducent
- Lateral squint, ptosis, mydriasis, loss of accomodation, slight proptosis and diplopia.
- Diplopia on looking downwards
- Medial squint and diplopia
Mention branches of opthalmic nerve
Frontal, nasociliary, lacrimal
The postganglionic parasymp fibers from ciliary ganglion reach target muscles via…….
Short ciliary nerves
Describe autonomic role of long ciliary n
Symp to dilator pupilae muscle
Sympathetic root of ciliary ganglion is from…..
Internal carotid art plexus (superior cervical ganglion)
Mention branches of ciliary ganglion
Eff post ganglion symp to bv. and para to ciliary m and constrictor pupilae
Afferent sensory from eye ball
Ophthalmic art passes between…..
SO and MR
Enumerate branches of ophthalmic art
Central retinal, posterior ciliary, miscluar, medial palpebral, lacrimal, and and post ethmoidal, supraorbital
Supratrochlear and dorsal nasal (terminal)
The artery which passes within substance of optic n is….
Central retinal art
Post ciliary arts supply….while ant supply…..
Choroid and iris
Ocular muscles
Enumerate branches of lacrimal branch of ophthalmic
Lateral palpebral, zygomatic, meningeal branchea
Medial palpebral arts supply……
Upper and lower eyelids
Lymphatics of orbit drain into…..
Pre-auricular (parotid) LN
Palpebral part of o.oculi m is found in….
Superficial fascia
Orbital seprum is formed by……, while…….are found at lid margins and stiffen them.
Palpebral fascia
Tarsi
Describe blood supply of eyelids
Art, medial and lateral palpebral ligaments
Ven, ophthalmic and facial veins
Describe nerve syupply of eyelids
Upper eyelid by branches of ophthalmic
Lower eyelid by branches of infraorbital
Describe lymph drainage of eyelids
Med to submandibular nodes
Lat to preauricular nodes
Write a short note of sources of each structure of the eye
Neuroectoderm: optic n, retina, ciliary body, iris
Surface ectoderm: lens vesicle, epithelium of cornea
Mesoderm: choroid, sclera, cornea ex epithelium, ant chamber, vitreous body
The optic vesicle appears in…..
End of 4th week
Outer layer of optic cup gives….
Post 4/5 of inner layer gives….
Ant 1/5 gives…..
Pigment layer of retina
Remaining layer of retina
Ciliary body and iris
The lips of choroid fissure fuse during….., the mouth optic cup forms…., the hyaloid artery forms…., the optic stalk forms…..
7th week
Pupil
Central retinal art
Optic nerve
In the eye, …..corresponds to pia, while……corresponds to dura
Vascularized pigmented choroid layer
Sclera
Describe the results of vacuolization of mesenchyme of the eye
Anterior chamber is formed with iridopupillary membrane inside and substantia propria of the cornea outside.
Mention the results of incomplete resorption of iridopupillary membrane
CT strands in front of the pupil
A cleft in lower part of iris is called….., while the absence of the eye is called…..
Coloboma iridis
Anophthalmia
Describe an infectious cause of congenitak cataract
German measles infection between 4th and 7th weeks
Mention infectious causes of microphthalmia
CMV & toxoplasmosis
1st order of neuron of visual pathway is……while 2nd order neuron is……
Bipolar cells
Ganglion cells
Enumerate contents of each optic tract
- Contralateral nasal fibers
- Ipsilateral temporal fibers
- Macular fibers from both sides
Mention roots of optic tract and contents
Med root contains supraoptic commissure of Gudden which connect MGBs
Lat root contains visual fibers than terminate on LGB, some pass to pretectal nucleus and superior colliculus.
With regards 3rd order neuron of visual pathway, dorsal group………., while ventral group……. . Both…….
End in pareital lobe (from upper quadrant)
Makes loop of Meyer in temporal lobe (from lower quadrant)
Join together in occipital lobe to end in cortical visual area
Describe extension of area 17
Below precalcarine sulcus, on both sides of postcalcarine sulcus extending to occipital pole
Describe S,F & lesion of visual association areas
Around area 17
F, store past visual experience to identify objects and discriminate colours, occipital eye field is resposible for involuntary reflex conjugate eye movements
L, visual agnosia
Describe results of lesions in optic n
Optic neuritis, circuferential blindness
Resection, ipsilateal total blindness
Describe results of lesions in optic chiasma
Lat pressure: ipsilateral nasal hemianopia (ICA aneurysm)
Med pressure: bilateral temporal hemianopia (pituitary tumours)
Describe results of lesions after optic chiasm in visual pathway
Total lesion leads to contralateral homonomous hemianopia
Upper lesion leads to CL lower quadrantic anopia
Lower lesion leads to CL upper quadrantic anopia
Describe pathway of light reflex from pretectal nucleus to pupil
Prectectal n to EWN of CN III through inf division of oculomotor then nerve to IO then ciliary ganglion then gives, in short ciliary, nerve postganglionic parasymp fibers to sphincter pupilae muscle
Mention components of near response reflex
Convergence of eyes by MR
Increased refractive power of lens by ciliary muscle
Pupillary constriction
Describe pathway of accomodation reflex
Optic n till visual area in occipital lobe (visual pathway) then it sends to frontal eyefield in frontal lobe through the superior longitudinal bundle then descend in internal capsule and relay on pretectal nuclei then to oculomotor nuclei both EWN & motor nucleus of CN III (for medial rectus contraction)
Describe pathway for corneal reflex
Afferents along ophthalmic n to main sensory nucleus of trigeminalpass via an interneuron to motor n of CN VII, causing contraction of orbicularis oculi and closure of eyelids
