Flashcards in head: orbit Deck (120)
orbit: Pyramid-shaped w/ ________ base +________ apex
what angles are the medial and lateral walls of the orbit to each other?
Medial walls parallel
Lateral walls at 90° to each other
what angles are the axis of the orbits at to each other? what about axis of neutral gaze?
Axis of orbits at 45° to each other
Axis of neutral gaze parallel
what lines the orbit?
Lined by periorbita-periosteum of orbit
what bones make up the orbit opening of the face (aka the base) ?
Reinforced portions of frontal, zygomatic, & maxillary bones
what make up the superior wall of the orbit?
Orbital portion of frontal bone
Lesser wing of sphenoid
what bone can you find the anterolateral fossa for lacrimal gland?
orbital portion of frontal bone (forming the superior wall)
where bones are the superior and inferior orbital fissures between? what wall does each separate in the orbit?
superior orbital fissure: optic canal between lesser and greater wings of sphenoid (separates lateral wall from apex)
inferior orbital fissure: between maxilla and greater sphenoid (separates lateral wall from inferior wall)
what 4 bones make up the median wall of the orbit?
Orbital plate of ethmoid
Frontal process of maxillary bone
what are the two features on the medial wall of the orbit?
lacrimal bone: fossa for nasolacrimal duct
attachment of trochlea for superior oblique
what bones makes up the inferior wall of the orbit?
which is the most exposed portion of the orbit (which wall)?
what bones make up the lateral wall of the orbit?
Frontal process of zygomatic bone
Greater wing of sphenoid
what is the apex of the pyramid that is the orbit ?
Optic canal in lesser wing of sphenoid
what is the palpebra conjunctiva? what does it reflect onto?
internal lining of eyelid (palpebra)
Reflects onto anterior surface of eyeball
which conjunctiva is directly on the sclera and attaches to it from the border of the cornea?
bulbar conjunctiva (vascular)
what is the space between the palpebra + bulbar conjunctiva . what is the significance of this location?
Conjunctival sacs (superior & inferior)
- where you administer eyedrops
what is the "tarus"? what do they do?
on inner side of eyelid: Dense connective tissue containing tarsal glands
Secrete lipid to prevent sticking & resist tear drainage
orbital septs extend from _____ to _______ ______. what is their purpose?
Orbital septa extend from tarsus to orbital margin
Limits spread of infection to/from orbit to face (act as barrier)
what muscle is anterior/superficial to tarsus? (on eyelid)
Palpebral portion of orbicularis oculi
what are the medial and lateral canthus of the eye?
Palpebral commissures-medial & lateral junctions
medial/lateral palpebral ligaments extends from where to where? what is the significance of the medial palpebral ligament?
from medial/lateral canthus out to orbital margin(bone)
- Origin & insertion of orbicularis oculi
what 4 structures does the "lacrimal apparatus" include?
- lacrimal gland
- 2 lacrimal papillae
- lacrimal sac
- nasolacrimal duct
lacrimal gland: where is it? what does it contain? what is its purpose?
Fossa of superolateral orbit
8-12 excretory ducts drain into superior conjunctival sac
(Isotonic saline with lysozyme)
Lubricates conjunctiva & cornea
what do the lacrimal papillae/canaliculi do?
Drain tears from lacrimal lake at medial canthus
what is the path of secretomotor innervation of the lacrimal apparatus? ( pregang, enters where and becomes what nerve, synapses, postgang)
Preganglionic fibers travel in CN VII (Greater petrosal branch)
Enters pterygoid canal as nerve of pterygoid canal
Synapse in pterygopalatine ganglion (synapse occurs here)
Postganglionic fibers travel in CN V2, then CN V1. after synapse...
CN V2- Infra-orbital
CN V1 - Lacrimal
eye muscles: which two do elevation, which two do depression?
inferior oblique and superior rectus: elevation
inferior rectus and superior oblique : depression
what is the most superior muscle in the orbit space?
Levator Palpebrae Superioris
Levator Palpebrae Superioris: O, I, A, Inn
O-lesser wing of sphenoid, superior to optic canal
I-tarsus & skin of superior lid
A- Elevates superior lid
Inn- oculomotor nerve (CN III)