DocGuy
ANATOMY
Medicine Made Simple
, Orbit & Eye
Orbit
Orbital Skeleton
Orbital margin
Above – frontal bone
Lateral – frontal & zygomatic
Inferior – zygomatic & maxilla
Medial – maxilla & frontal
Walls
Roof – orbital plate of frontal bone & lesser wing of sphenoid
Lateral – zygomatic & greater wing of sphenoid
Floor – orbital plate of maxilla, zygomatic, palatine bone
Medial – anterior lacrimal crest on frontal process of maxilla, posterior lacrimal crest on lacrimal, orbital plate
of ethmoid, body of sphenoid
Clinicals
1. In blow out fracture, orbital floor or medial wall may be damaged.
2. Fracture of floor causes herniation of orbital fat into maxillary sinus
3. Entrapment of an extra-ocular muscle causing diplopia
4. Injury to infra-orbital nerve
Openings
Supra orbital notch - supraorbital nerve & vessels
Infraorbital groove - infraorbital nerve & vessels. Lodges the orbitalis muscle
Nasolacrimal canal - nasolacrimal duct
Inferior orbital fissure - maxillary & zygomatic nerves, branch of inferior ophthalmic vein, sympathetics
(gap between lateral wall and floor)
Superior orbital fissure - L, F, T, S, O, N, I, A
(gap between lateral wall and roof)
Optic canal - optic nerve & ophthalmic artery
Anterior & posterior ethmoidal foramina – at the junction of roof and medial wall. Transmits the anterior &
posterior ethmoidal nerves & vessels
ANATOMY
Medicine Made Simple
, Orbit & Eye
Orbit
Orbital Skeleton
Orbital margin
Above – frontal bone
Lateral – frontal & zygomatic
Inferior – zygomatic & maxilla
Medial – maxilla & frontal
Walls
Roof – orbital plate of frontal bone & lesser wing of sphenoid
Lateral – zygomatic & greater wing of sphenoid
Floor – orbital plate of maxilla, zygomatic, palatine bone
Medial – anterior lacrimal crest on frontal process of maxilla, posterior lacrimal crest on lacrimal, orbital plate
of ethmoid, body of sphenoid
Clinicals
1. In blow out fracture, orbital floor or medial wall may be damaged.
2. Fracture of floor causes herniation of orbital fat into maxillary sinus
3. Entrapment of an extra-ocular muscle causing diplopia
4. Injury to infra-orbital nerve
Openings
Supra orbital notch - supraorbital nerve & vessels
Infraorbital groove - infraorbital nerve & vessels. Lodges the orbitalis muscle
Nasolacrimal canal - nasolacrimal duct
Inferior orbital fissure - maxillary & zygomatic nerves, branch of inferior ophthalmic vein, sympathetics
(gap between lateral wall and floor)
Superior orbital fissure - L, F, T, S, O, N, I, A
(gap between lateral wall and roof)
Optic canal - optic nerve & ophthalmic artery
Anterior & posterior ethmoidal foramina – at the junction of roof and medial wall. Transmits the anterior &
posterior ethmoidal nerves & vessels
