Anatomy: Bony Orbit

Question 1

Bony orbit

Answer 1

Bilateral and symmetrical cavities in the head. Enclose the eyeball and its associated structures.

Question 2

Bony Orbit Relations

Answer 2

Roof
- frontal bone and the lesser wing of the sphenoid.

Floor
- maxilla, palatine and zygomatic bones

Medial
- ethmoid, maxilla, lacrimal and sphenoid bones

Lateral.
- zygomatic bone and greater wing of sphenoid

Apex
- opening to optic canal (optic foramen)

Base

• orbital rim
• opens out into face and is bounded by eyelids

Question 3

Bony Orbit Contents

Answer 3

Extra-ocular muscles
Eyelids
Nerves
Blood Vessels

Any space within the orbit that is not occupied is filled with orbital fat

Question 4

Pathways into bony orbit

Answer 4

Optic Canal
Superior Orbital Fissure
Inferior orbital fissure

Question 5

Optic Canal

Answer 5

Transmits the optic nerve and ophthalmic artery

Question 6

Superior Orbital Fissure

Answer 6

Transmits the lacrimal, frontal, trochlear, oculomotor, nasociliary and abducens nerves
Also carries the superior ophthalmic vein

Question 7

Inferior orbital fissure

Answer 7

Transmits zygomatic branch of the maxillary nerve, inferior ophthalmic vein and sympathetic nerve

Question 8

Minor openings into orbital cavity

Answer 8

Nasolacrimal canal
- drains tears from eye to nasal cavity

Supraorbital foramen

Infraorbital Canal

Question 9

Fractures of the Bony Orbit

Answer 9

Orbital Rim Fracture

Blowout fracture

Question 10

Orbital Rim Fracture

Answer 10

Fracture of bones forming the outer rim of the bony orbit.
Usually occurs at. the sutures joining the 3 bones of the orbital rim
- maxilla
-zygomatic
-frontal

Question 11

Blowout Fracture

Answer 11

Partial herniation of the orbital contents through one of its walls
usually occurs via blunt force trauma to the eye
Medial and inferior walls are the weakest, contents herniate into ethmoid and maxillary sinuses.