Orbit Flashcards
bone roof of orbit
frontal
bone medial wall of orbit
ethmoid (posteriorly) and lacrimal (anteriorly)bones
lateral wall of orbit
sphenoid (posteriorly) and zygomatic (anteriorly)
floor of orbit
maxilla
what occurs in an orbital blowout fracture
forces transmitted to thinner walls of the orbit cause fracture and contents hemorrage medially into ethmoid air cells or inferiorly into maxillary sinus
which walls of the orbit are at higher risk of blowout fracture
floor (maxilla) and (posterior) medial wall (ethmoid)
what are the consequences of orbital blowout fx
hemorrhage into: 1. ethmoid air cells (medially) 2. maxillary sinus (inferiorly)
describe medial wall of orbit
are parallel
describe lateral walls of orbit
converge at 90degrees at the hypophyseal fossa
describe the optic axis
follows the line of gaze, should always be parallel to each other (parallel to medial walls)
describe orbital axis
follows axis of orbit itself, follows the apex through the center of the orbit
what is bulbar conjunctiva
conjunctiva covering the eye itself, but stops at limbus (doesn’t cover cornea)
what is palpebral conjunctiva?
inner surface of the eyelid that reflects onto the eyeball itself (becomes the bulbar conjunctiva)
describe the folding of the conjunctiva
palpebral conjunctiva folds and becomes the bulbar conjunctiva, the space between the 2 is called superior conjunctiva fornix
what is superior and inferior conjunctival fornix?
blind ended culdesac, made up of the palpebral and bulbar conjunctiva
what are ciliary glands?
sebaceous/sweat glands at the base of each eyelash
what are tarsal glands?
glands within the skeleton of the eyelid, lubricates eyelid and prevents the eyelid from sticking to the eyeball
what is a chalazion
blockage of tarsal glands that manifests as a small, PAINLESS bump on eyelid
what is a stye
INFECTION of ciliary (sebaceous) glands of the eyelid. are PAINFUL and purulent
innvervation of levator palpebrae superioris
CNIII (oculomotor)
innervation of superior tarsus
sympathetics
innervation of orbicularis oculi
CN VII facial nerve
what muscles elevate the eyelid?
- levator palpebrae superioris
- superior tarsus
what muscle closes the eye?
orbicularis oculi
describe orbital part of orbicularis oculi
around orbital rim, hard closure of the eye
describe palpebral part of orbicularis oculi
covers the eyelash itself, soft closure of the eye
what is ptosis
drooping of the upper eyelid
what causes ptosis
weakness of denervation of
- superior tarsus (sympathetics)
or
- levator palpebrae superioris (CNIII)
sensory innervation of the eyelids
- V1 – supraorbital nerve, lacrimal nerve, supratrochlear nerve, infratrochlear nerve
- V2 – infraorbital nerve
what makes the superior and inferior tarsal plates?
the continuation of periosteum (orbital septum) thickens above and below eye
what does the orbital septum do?
keeps content of orbit within the orbit, prevents hemorrhaging out of the face; is a continuation of periostum covering the bones of the face
origin of orbicularis oculi?
medial palpebral legament
what makes up the medial and lateral palpebral ligaments?
thickened orbital septum medially and laterally
origin of levator palpebrae superioris
superior tarsal plate
flow of lacrimal apparatus
- lacrimal gland
- lacrimal ducts
- lacrimal puncta
- lacrimal canaliculi
- lacrimal sac
- nasolacrimal duct
- nasal cavity through inferior nasal meatus
