The Orbit

Question 1

the boundaries of the orbit are formed by how many bones?

Answer 1

7

Question 2

what are the borders of the orbit?
* roof
* floor
* medial wall
* lateral wall
* apex
* base

Answer 2

• roof - frontal bone + lesser wing of sphenoid
• floor - maxilla, palatine, zygomatic
• medial wall - ehtmoid, maxilla, lacrimal, sphenoid
• lateral wall - zygomatic + greater wing of sphenoid
• apex - optic foramen
• base - orbital rim

Question 3

?

what separates the orbit from the anterior cranial fossa

Answer 3

frontal bone

Question 4

what separates the orbit from the maxillary sinus?

Answer 4

maxilla

Question 5

what separates the orbit from the ethmoid sinus?

Answer 5

ethmoid

Question 6

what does the orbit contain?

Answer 6

• eyeballs
• extra-occular muscles
• eyelids
• nerves
• blood vessels
• orbital fat

Question 7

any space in the orbit that is not occupied is filled by what?

Answer 7

orbital fat

Question 8

what is the role of orbital fat?

Answer 8

cushions the eye and stabilises the extraocular muscle

Question 9

what is the arterial supply of the eye?

Answer 9

opthalmic artery

Question 10

what is the venous drainage of the eye?

Answer 10

superior and inferior opthalmic veins

Question 11

what are the 3 main pathways by which tructures can enter and leave the orbit?

Answer 11

• optic canal
• superior orbital fissure
• inferior orbital fissure

Question 12

what travels through the optic canal?

Answer 12

optic nerve
opthalmic artery

Question 13

what travels through the superior orbital fissure?

Answer 13

nerves:
* lacrimal
* frontal
* trochlear - CN IV
* oculomotor -CN III
* nasociliary
* abducens - CN VI

superior opthalmic vein

Question 14

what travels through the inferior orbital fissure?

Answer 14

• zygomatic branch of maxillary nerve
• inferior ophthalmic vein
• sympathetic nerves

Question 15

label the bones of the orbit

Answer 15

Question 16

Label the major openings into the orbit

Answer 16

Question 17

what is the role of the nasolacrimal canal?

Answer 17

drains tears from the eye to the nasal cavity