orbit

Question 1

What is the orbital cavity

Answer 1

they are a set of two pyramidal-shaped bony cavities with the medial walls parallel and the lateral walls perpendicular. Looking forward is considered primary postition of the eyeball which is not the same as the angle of the orbital cavity, differs by 23 degrees inward

Question 2

bones that form the orbital margins

Answer 2

supraorbital- frontal bone and supraorbital notch
lateral- frontal bone and zygomatic bone
infraorbital- zygomatic bone and maxilla
medial- maxilla and frontal bone

Question 3

orbit wall components and features

Answer 3

roof- orbital plate of frontal and lacrimal fossa
lateral- zygomatic and greater wing of sphenoid b, and superior orbital fissure (communicates with the middle cranial fossa)
floor- orbital plate of maxilla, inferior orbital fissure, infraorbital groove(canal/foramen)
medial -bone

Question 4

anatomy of eyelids and layers

Answer 4

palpebral fissure- opening between two eyelids
canthi-medial and lateral angles (corners of eye)
four layers of lid- skin, muscle, tarsal plates and orbital septum, cunjunctiva

Question 5

skin of eyelid

Answer 5

relatively thin compared to the rest of the body and is continuos with the conjunctiva, at margin is where the eyelashes are and it has sebaceous glands and sweat glands
has ctissue

Question 6

muscle layer of eyelid

Answer 6

palpebral part of orbicularis oculi muscle, with sub muscular connective tissue

Question 7

tarsal plates and orbital septum

Answer 7

below skin and muscle is the dense connective tissue thats subdivided into tarsal plates and orbital septum:

the two tarsal plates:
the superior one is an oval and the inferior one is a crecent shape. some fibers of the levator palpebrae superioris will connect to the superior tarsal plate. the superior tarsal plate also contains the superior tarsal muscle which a smooth muscle that is autonomincally innervated. the tarsal plates have the tarsal glands which add an oil to tears to help them not evaporate too quickly. the tarsal plates are connected to the bones by medial and lateral palpebral ligaments.

orbital septum: the part of the connective tissue that isnt directly on the eyeball itself

Question 8

conjuctiva of the eyelid

Answer 8

tissue that lines the inside the eyelid,
palpebral: lines the eyelid
fornix (superior and inferior): where the palpebral conjunctiva takes a hairpin turn to actually touch the eyeball
bulbar: covering anterior surface of sclera and cornea as corneal epithelium

the superior fornix recieves ducts of lacrimal glands, secretes tears

Question 9

anatomy of the eyeball

Answer 9

lens- transparent, biconvex, held in place by ragdiating zonule fibers(pull on lens and controll thinckness), the lens is made of lens fibers

anterior cavity- filled with aqueous humor, further subdivided into anterior chamber(between iris and cornea) and posterior chamber(between iris and lens)

posterior cavity- contains vitreous humor has a hyloid canal (remnant of dev)

Question 10

tunics of the eyeball

Answer 10

fibrous tunic: Sclera and cornea. Sclera is the white fibrous dense connective tissue(insertion of extraocular muscles) pierced posteriorly by the optic nerve (weak area, pierced by ciliary arteries. At corneal, scleral junction is the cornea which is a major refractive structure thats transparent and avascular

vascular tunic: contains the choroid posteriorly, contains vessels to supply the cells of the retina, and anteriorly is the ciliary body which has epithelium that secretes aqueous humor and also has the ciliary muscle(control the shape of lens by pulling on zonule fibers, contract andgive slack to the lens).*glaucoma, vascular tunic also has iris, pupil contain circular muscles spincter pupillae and dialator pupillae

retina- neural layer

Question 11

the path of aqueous humor in the eye

Answer 11

aqueous humor gets made by ciliary body epithelium then gets pushed into the posterior chamber then goes to the anterior chamber then gets reabsorbed in the canal of shlem to go back to the venous system

Question 12

lacrimal apparatus

Answer 12

lacrimal gland- superolateral, ducts drain into superior fornix

lacrimal puncta- openings in lacrimal papilla, and drain viea lacrimal canaliculi then got to lacrimal sac then go to lacrimal duct to inferior nasal meatus

Question 13

ophthalmic artery

Answer 13

central a of the retina
lacrimal a (lateral)
supraorbital a
dorsal nasal a
supra trochlear a
posterior and anterior ethmoidal a

Question 14

veins of orbital region

Answer 14

central v of the retina, superior ophthalmic v and inferior ophthalmic v

Question 15

special sensory innervation of orbital region

Answer 15

optic nerve

Question 16

somatic sensory innervation of the orbital region

Answer 16

ophthalmicperipheral process transmits sensation from sensory receptors thru superior orbital fissure thru cavernous sinus, neuron cell bodis in trigeminal ganglion

Question 17

motor innervation of orbital region

Answer 17

cn 3 4 6 (LR6 SO4)3

Question 18

autonomic innervation of orbit

Answer 18

lacrimal gland, sphincter pupillae +ciliarym., Dilator pupillae +superior tarsal

Question 19

parasympathetic innervation of lacrimal nerven

Answer 19

superior nuc—(CN VII)–>geniculate ganglion—greaterpetrosal n. + deep petrosal n=nerve of pterygoid canal—> pterygopalatine ganglion—> zygomaticotemporal n and lacrimal n. allow lacrimal gland to secrete

Question 20

sympathetic innervation of the lacrimal gland

Answer 20

lateral horn of spinal cord(T1-L2)–>