orbit Flashcards
bones that contribute to the orbit
- frontal
- zygomatic
- maxilla
- lacrimal
- ethmoid
- sphenoid
- palatine
location of common tendinous ring
- surrounds the optic canal
- surrounds portion of SOF
what structures are involved in the sella turcica
- tuberculum sellae
- dorsum sellae
- hypophysial fossa
names of pterygoid processes
- medial plate
- lateral plate
osteology of the orbit in the anterior view and coronal section
- frontal bone
- crista galli and perpendicular plate of ethmoid
- vomer
- sphenoid –> greater and lesser wings, optical canal and SOF
- infraorbital groove and infraorbital canal
what is involved in the contents of the orbit
- eyeball
- extra-ocular muscles
- neurovascular structures
- lacrimal gland
- oribital fat
name the muscles that control movement of the eyeball
rectus muscles –> superior, inferior, medial, lateral
oblique muscles –> superior and inferior
name the muscle that evaluates the superior eyelid
levator palpebrae superioris
origin and insertion of rectus muscles
origin –> common tendinous ring
insertion –> sclera - anterior to equator of eyeball
origin and insertion of superior oblique
origin –> body of sphenoid bone
insertion –> sclera - posterior to equator of eyeball
purpose of trochlea/tendinous pulley for superior oblique
- attaches to frontal bone
- redirect superior oblique backwards to its insertion
origin and insertion of inferior oblique
origin –> orbital surface of maxilla (anterior aspect of orbit)
insertion –> sclera - posterior to equator of eyeball
extra-ocular muscles
- 4 rectus muscles
- 2 oblique muscles
origin and insertion of levator palpebrae superioris
origin –> lesser wing of sphenoid bone
- insertion –> superior eyelid
what does the oculomotor nerve innervate
- superior, medial and inferior rectus
- inferior oblique
- levator palpebrae superioris
what does the abducent nerve innervate
lateral rectus
what does the trochlear nerve innervate
superior oblique
what nerve exits through optical canal
optical nerve (CN 2)
what exits through SOF
- oculomotor nevre (CN 3)
- trochlear nerve (CN 4)
- ophthalmic division of trigeminal (CN V1)
- abducent nerve (CN 6)
what is the diaphragma sellae
- horizontal shelf of meningeal dura mater
- forms roof od\f the sella turcica
- cover pituitary gland
- infundibulum/ stalk of the pituitary gland passes through diaphragma sellae
what is the cavernous sinus
- dura covers the lateral and superior walls
- CN 3,4,6 passes through
- CN 3 and 4 travel on lateral wall
- CN 6 travels close to internal carotid artery
risk of CN6 travelling close to internal carotid artery in cavernous sinus
can be damaged in cases of intra-cavernous aneurysm of internal carotid artery
