Flashcards in Orbit and the Eye Pt. 1 Deck (31)
Seven Bones of the Orbit
Four walls of the orbits
Lateral, medial, roof and floor
Lateral Wall consists of:
zygomatic bone and greater wing of the sphenoid bone.
Ethmoid and lacrimal bones
(and includes the anterior and posterior ethmoidal foramina int he frontosphenoid suture)
Orbital plate of the frontal bone
Orbital surface of the maxilla, very thin.
The inferior orbital fissure is continuous with the ___________ canal which opens onto the face via the infraorbital foramen.
Eyeball is about ____ cm in diameter
True/False: There are no lymph vessels in the orbit.
The orbit contains (8):
(2) orbital fascia
periorbita (periosteum lining bones of orbit)
common tendinous ring (origin of the four rectus muscles)
Rectus muscle origin and insertion?
Origin: common tendinous ring
Insert: anterior half of the eye
Obliques and levator origin and insertion
origin: bones of orbit
insert: obliques - posterior half of eye
levator palpebrae superioris - superior tarsus (upper eyelid)
Lateral and medial rectus actions?
Lateral: ABducts eye
Medial: ADducts eye
Inferior and superior oblique muscle actions?
Inferior Oblique: Up and Out
Superior Oblique: Down and Out
Superior and inferior rectus muscle actions?
Superior Rectus: Up and In
Inferior Rectus: Down and In
SR + SO Intort/extort eye?
IR + IO intort/extort eye?
IO and SR
SO and IR
LR + IO + SO
MR + IR + SR
SO and IO raise and lower eye when held in AB/ADduction?
SR and IR raise and lower eye when held in AB/ADduction?
Special Afferent (SA)
Optic Nerve (II)
Optic nerve carries SA fibers from retina to the visual centers of the brain. Has dural coverings; extension of the brain.
General Afferent (GA)
Ophthalmic Nerve (V1) which contains:
1. Frontal n.
2. Lacrimal n.
3. Nasociliary n.
Long ciliary nerves (general afferents from the eye)
General Efferent (GE)
Oculomotor Nerve (III) --> all EOMs except:
Trochlear Nerve (IV) --> sup. oblique m.
Abducent nerve (VI) --> lat rectus m.
- Loss of LR m (out)
- affected eye turns medially
- loss of SO m (down and out)
- Head is tilted away from the affected side
- Affected eye is slightly higher and deviated medially.
- may have diplopia.