Orbit

Question 1

Bony orbit

Answer 1

Pyramidal shaped narrow from behind forming apex (optic canal) and wide from in front forming orbital opening in face.
It has 4 walls:
1. Roof
2. Floor
3. Medial wall
4. Lateral wall

Question 2

Roof (2)

Answer 2

1. Orbital plate of frontal bone (main part)
2. Lesser wing of sphenoid (most posterior part)
   Contains lacrimal fossa in its anterolateral part for lacrimal gland

Question 3

Floor (2)

Answer 3

1. Orbital surface of maxilla (main part)
2. Orbital surface of zygomatic bone (anterolateral part)
   Contains Infraorbital groove and canal

Question 4

Medial wall (4)

Answer 4

1. Frontal process of maxilla
2. Lacrimal bone
3. Orbital surface of ethmoid bone
4. Body of sphenoid (from before backwards)

Question 5

Lateral wall (2)

Answer 5

1. Greater wing of sphenoid (posterior)
2. Frontal process of zygomatic bone (anterior)

Question 6

Orbital fissures

Answer 6

1. Superior orbital fissure
2. Inferior orbital fissure

Question 7

Superior orbital fissure site and communication

Answer 7

Lies between lesser wing of sphenoid (in roof) and greater wing of sphenoid (in lateral wall)
Communicates orbit with middle cranial fossa

Question 8

Inferior orbital fissure site and communication

Answer 8

Lie between maxilla (in floor) and greater wing of sphenoid (in lateral wall).
Communicates orbit with Infratemporal and Pterygopalatine fossae

Question 9

Contents of orbit (6)

Answer 9

1. Eyeball
2. Extraocular muscles
3. Nerves (7)
4. Vessels (2)
5. Lacrimal apparatus
6. Pad of fat

Question 10

Contents of orbit: nerves (7)

Answer 10

1. Optic nerve: vision
2. Ophthalmic nerve: general sensation
3. Oculomotor nerve
4. Trochlear nerve
5. Abducent nerve
   3,4,5: motor to eyeball muscles
6. Sympathetic fibers: from superior cervical ganglion
7. Parasympathetic (ciliary) ganglion: attached to nasocilliary nerve

Question 11

Contents of orbit: vessels (2)

Answer 11

1. Ophthalmic artery
2. Ophthalmic vein