The Orbit

Question 1

Where in the orbit is the bone thickest

Answer 1

Apex and at the base whereas walls are thinner

Question 2

Which walls in the orbit are shorter

Answer 2

The lateral walls and more convergent and more recessed

Question 3

How many bones it the orbit made of

Answer 3

7

Question 4

List the bones which the orbit is made of

Answer 4

Maxilla
Zygomatic bone
Lacrimal bone
Palatine bone
Frontal bone
Ethmoid bone
Sphenoid bone

Question 5

What is the orbit lined with

Answer 5

Periosteum called periorbita

Question 6

Where does the medial orbit wall extend from

Answer 6

The anterior lacrimal crest (maxilla) to apex

Question 7

What is the lamina papyracea

Answer 7

Paper thin plate of bone overlaying ethmoid sinus

Question 8

Where is the fronto ethmoid suture

Answer 8

Is margin of medial wall and roof of orbit

Question 9

What suture does the floor of the orbit slope upwards to

Answer 9

Maxilloethmoid suture

Question 10

What is the floor separated by postero laterally from the lateral wall

Answer 10

The inferior orbital fissure

Question 11

What is the lateral wall of the orbit formed by

Answer 11

The zygoma anteriorly and greater wing of sphenoid bone posteriorly

Question 12

Which nerves pass through the lateral orbit wall foramina aspect

Answer 12

Zygomatico temporal and zygomatic facial nerves

Question 13

What is the rigid and convex roof orbit formed of

Answer 13

Almost entirely the frontal bone

Question 14

Where is the supra orbital notch in the roof of the orbit

Answer 14

At margin of medial 1/3 and lateral 2/3’s

Question 15

What is at the apex of the orbit

Answer 15

The optic foramen (canal) bound medially by body of sphenoid bone and laterally by lesser wing of sphenoid bone

Question 16

What does the optic foramen provide a passage for

Answer 16

The optic nerve and ophthalmic artery to exit the skull

Question 17

What are the 4 main contents of eyelids

Answer 17

Tarsal plate - maintains shape
Tarsal glands - secrete oily substance
Orbicularis oculi
Levator Palpebrae superioris

Question 18

What does the lacrimal canal groove open into

Answer 18

The inferior meatus of nose and transmits nasolacrimal duct

Question 19

What is the lacrimal groove

Answer 19

A deep groove in front of opening of maxillary sinus on nasal surface of maxilla which is converted into nasolacrimal canal

Question 20

What is the nasolacrimal canal made of

Answer 20

Lacrimal bone and inferior nasal concha

Question 21

What is inflammation of the lacrimal glands called

Answer 21

Dacryoadenitis

Question 22

What do tears drain through

Answer 22

Naso lacrimal duct into inferior meatus of nose

Question 23

What is the 5 list pathway of tears

Answer 23

Puncta lacrimalia
Canaliculi
Lacrimal sac
Nasolacrimal duct
Inferior meatus of lateral wall of nasal cavity

Question 24

Where is the anterior ethmoidal foramen

Answer 24

Found at junction between superior and medial orbital walls

Question 25

What does the anterior ethmoidal foramen transmit

Answer 25

Anterior ethmoidal vein, artery and nerve

Question 26

Where is the posterior ethmoidal foramen

Answer 26

Junction between superior and medial orbital walls

Question 27

What does the posterior ethmoidal foramen transmit

Answer 27

Posterior ethmoidal vein, artery and nerve

Question 28

What is the trochlear

Answer 28

Pulley like structure at orbital roof through which tendon of superior oblique muscle passes Only cartilage found in orbit

Question 29

What is the common tendinous ring

Answer 29

A fibrous ring which surrounds optic canal and part of superior orbital fissure at apex of orbit and give origin to 4 recti

Question 30

Which nerve supplies the superior oblique muscle

Answer 30

Trochlear nerve

Question 31

Which nerve supplies the lateral rectus

Answer 31

Abducens nerve

Question 32

Which is the oculomotor nerves 3 main motor functions

Answer 32

Innervation to pupil and lens Innervation to upper eyelid - Levator palpebrae superioris Innervation of eye muscles that allow for visual tracking and gaze fixation - superior, medial and inferior recti + inferior oblique

Question 33

What is the action of the lateral rectus

Answer 33

Abduction

Question 34

What is the action of the medial rectus

Answer 34

Adduction

Question 35

What is the action of the superior rectus

Answer 35

Up and in

Question 36

What is the action of the inferior rectus

Answer 36

Down and in

Question 37

What is the action of the superior oblique

Answer 37

Down and out

Question 38

What is the action of the inferior oblique

Answer 38

Up and out

Question 39

Where is the superior orbital fissure

Answer 39

Between the greater and lesser wings of sphenoid bone

Question 40

How is the superior orbital fissure shaped

Answer 40

Narrow supero laterally and broader infero medially

Question 41

List 6 nerves/veins that the superior orbital fissure transmits

Answer 41

Superior ophthalmic vein Branch of inferior ophthalmic vein Superior and inferior branches of oculomotor nerve Lacrimal, frontal and nasociliary branches of ophthalmic division of trigeminal nerve Trochlear nerve Abducens nerve

Question 42

List the 4 nerves/veins/artery the inferior orbital fissure transmits

Answer 42

Inferior ophthalmic veins Infraorbital artery Zygomatic and infraorbital branches of maxillary division of trigeminal nerve Orbital branches of Pterygopalatine ganglion

Question 43

Where is the inferior orbital fissure

Answer 43

On the lateral border of orbital floor

Question 44

What are the 4 contents of the infratemporal fossa

Answer 44

Temporalis muscle Maxillary artery and vein and associated branches Buccal and Temporalis fat pads Communicates with anterior part of IOF

Question 45

What re the 4 contents of the Pterygopalatine fossa

Answer 45

Pterygopalatine ganglion Maxillary nerve and its branches Infra orbital branch of maxillary artery Communicates with posterior part of IOF

Question 46

Where does the ophthalmic artery travel

Answer 46

With optic nerve through optic canal

Question 47

Where does the central artery of the retina travel

Answer 47

Middle of optic vein, passes into back of retina and spread out

Question 48

What does the ophthalmic vein connect with

Answer 48

Angular vein (facial)

Question 49

How do pre ganglionic parasympathetic fibres travel

Answer 49

With occulomotor nerve then relay in ciliary ganglion

Question 50

How do post ganglionic fibres travel

Answer 50

Pass to sphincter of iris and ciliary body by hitchhiking with branches of ophthalmic nerve

Question 51

What is the activity in the fibres in the ciliary ganglion responsible for

Answer 51

Mitosis and accommodation

Question 52

What are the 3 motor nerves of the orbit

Answer 52

Oculomotor nerve Trochlear nerve Abducens nerve

Question 53

What are the 3 sensory nerves of the orbit

Answer 53

Ophthalmic nerve Maxillary nerve Optic nerve

Question 54

What 5 muscles does the oculomotor innervate

Answer 54

Levator palpebrae superioris Superior, medial and inferior rectus Inferior oblique

Question 55

What muscle does the trochlear nerve innervate

Answer 55

Superior oblique

Question 56

What muscle does the abducens innervate

Answer 56

Lateral rectus

Question 57

What separates the eyeball from orbital muscles and fat

Answer 57

Fascial sheath

Question 58

What is the eye suspended in place by

Answer 58

Check ligaments and suspensory ligament of Lockwood