Orbit and eye Flashcards
orbital cavity (ORBIT)
Orbit: quadrangular pyramid, with base anteriorly, apex posteriorly, and 4 walls
- lacrimal bone
- orbital plate of ethmoidal lamina (lamina papyracea)
- frontal bone
- sphenoid bone
- orbital process of palatine bone
- zygomatic bone
- maxilla
- superior orbital fissue
- inferior orbital fissure
*orbit
lacrimal bone
- contribute to medial wall of orbit.
- contains fossa for lacrimal sac
orbital plate of ethmoid lamina (lamina papyracea)
- posterior to the lacrimal bone, very thin bone.
- contribute to medial wall of the orbit
frontal bone
contribute to superior wall (roof) of the orbit
sphenoid bone
- greater wing contribute to lateral wall, while lesser wing contribute to superior wall near the apex of the orbit
- optic canal: though the lesser wing
orbital process of palatine bone
contribute slightly to apex of orbit
zygomatic bone
contribute significantly to lateral wall of orbit
maxilla
contribute significantly to inferior wall of orbit
superior orbital fissure
located between the greater and lesser wings of the sphenoid
inferior orbital fissure
between maxilla, zygomatic, and greater wing of the sphenoid
orbital content
- eyelids
- extraocular mm
- nerves and vessels
- orbital fascia
- muscous membrane (conjuctiva)
- (rest of the orbital space is occupied by orbital fat, embedding structures)
eyelids
bound orbit anteriorly, limiting exposure of anterior eyeball
extraocular mm
position the eyeball and raise superior eyelid
orbital fascia
surrounds eyeball and mm
conjunctiva
- mucous membrane
- lining of the anterior aspect of the eyeballs, interior aspect of eyelids, and most of the lacrimal apparatus
eyelid components
- Moveable folds covering and protecting the eyeball anteriorly
- Keep cornea moist by spreading lacrimal fluid
- Components
- Skin
- connective tissue: contains eyelashes
- skeletal mm: orbicularis oculi mm
- tarsofascial layer
- conjunctiva: inner layer of eyelid
sphincter of the eye
orbicularis oculi mm
tarsofascial layer:
- superior and inferior tarsi
- orbital septum
- tarsal glands
dense bands of connective tissue, strengthening the eyelids
superior and inferior tarsi
continuation of the periosteum of the bones surrounding the orbit (frontal, zygomatic, and maxillary). attached to the tarsi
orbital septum
sebaceous glands, whose lipid secretion resists the overflow of tear
tarsal gland
inner layer of eyelid and its 2 parts
- conjuctiva:
- palpebrae conjunctiva: closer to eyelid and it is opaque
- bulbar conjuctiva: overlies the cornea and it is transparent. receives sensory innervation from the long ciliary n.
space bund by the bulbar and palpebral conjuctiva
conjunctival sac
junctions of the superior and inferior eyelids. Form the medial and lateral angles (canthi) of the eye
medial and lateral palpebra commissures
connects tarsi to medial margin of orbit
medial palpebral ligament
connects tarsi to lateral margin of orbit
Lateral palpebral ligament
*eyelid (lateral view)
*eyelid (anterior view)
lacrimal appartus (includes):
- lacrimal glands
- excretory ducts
- lacrimal canaliculi
- lacrimal sac
- nasolacrimal duct
*lacrimal apparatus
secretes lacrimal fluid and is divided into superior (orbital) and inferior (palpebral) parts
lacrimal glands
location of lacrimal glands
in the superior lateral part of the orbit. in a little depression in the frontal bone called the lacrimal fossa (about 2 cm in diameter and oval-shaped)
a watery physiological saline solution secreted though 8-12 excreotry ducts
lacrimal fluid
convey lacrimal fluid to the conjunctival sac
excretory ducts
small canals that begin at the lacrimal punctum (opening) on the lacrimal papilla in the medial angle of the eye
lacrimal canaliculi