orbit

Question 1

what makes up the roof of the orbit (1 thing)

Answer 1

orbital plate of frontal bone

Question 2

what makes up the floor of the orbit (1 thing)

Answer 2

orbital plate of maxilla

Question 3

what makes up the lateral wall of the orbit (2 things)

Answer 3

zygoma, greater wing of sphenoid

Question 4

what makes up the medial wall of the orbit (4 things)

Answer 4

frontal process of maxilla, lacrimal bone, orbital plate of ethmoid (lamina papyracea), lesser wing of sphenoid

Question 5

what foramen lies above the orbit in the orbital plate of frontal bone

Answer 5

supraorbital foramen

Question 6

what foramen lies below the orbit in the frontal process of maxilla

Answer 6

infraorbital foramen

Question 7

what section of the orbit can be blown out by a squashball injury, and consequence

Answer 7

orbital plate of maxilla, causing eye to drop into cheek cavity (causing double vision)

Question 8

3 orbital foramina

Answer 8

optic canal, inferior orbital fissure, superior orbital fissure

Question 9

2 contents of optic canal

Answer 9

optic nerve (CN II) to back of globe, ophthalmic artery

Question 10

2 contents of inferior orbital fissure

Answer 10

maxillary nerve (CN V2), infraorbital vessels

Question 11

6 contents of superior orbital fissure

Answer 11

ophthalmic nerve (CN V1), oculomotor nerve (CN III), trochlear nerve (CN IV), abducens nerve (CN VI), ophthalmic vessels, sympathetic fibres

Question 12

which bone is the optic canal embedded in

Answer 12

lesser wing of sphenoid bone

Question 13

where does the superior orbital fissure lie

Answer 13

between the lesser and greater wings of sphenoid bone

Question 14

what 2 bones form the inferior orbital fissure

Answer 14

sphenoid bone and maxilla

Question 15

where does the maxillary nerve exit through the maxilla bone inferior to the orbit

Answer 15

infraorbital foramen

Question 16

2 groups of extrinsic eye muscles, and how many of each

Answer 16

4 recti, 2 obliques

Question 17

what are the 4 recti muscles

Answer 17

inferior, superior, medial, lateral

Question 18

origin of recti muscles

Answer 18

back of orbit in common tendinous ring

Question 19

where do recti muscles insert into the eye

Answer 19

sclera, 5mm behind corneal margin

Question 20

nerve supplying inferior, superior and medial recti

Answer 20

oculomotor (CN III)

Question 21

nerve supplying lateral rectus

Answer 21

abducens (CN VI)

Question 22

what are the 2 oblique muscles

Answer 22

inferior, superior

Question 23

origin of inferior oblique

Answer 23

orbital surface of maxilla

Question 24

origin of superior oblique

Answer 24

body of sphenoid

Question 25

where does inferior oblique insert onto eye

Answer 25

posterior/inferior quadrant

Question 26

where does superior oblique insert onto eye, and via what

Answer 26

poserior/superior lateral quadrant of globe, via trochlea

Question 27

nerve supplying inferior oblique

Answer 27

oculomotor (CN III)

Question 28

nerve supplying superior oblique

Answer 28

trochlear (CN IV)

Question 29

what is the muscle of the upper eyelid

Answer 29

levator papebrae superioris (LPS)

Question 30

origin of LPS

Answer 30

lesser wing of sphenoid

Question 31

where does LPS insert

Answer 31

superior tarsal plate and skin of eyelid

Question 32

nerves supplying LPS

Answer 32

oculomotor (CN III), sympathetic to smooth muscle

Question 33

what syndrome is associated with loss of sympathetic supply to head

Answer 33

Horner's syndrome

Question 34

how does LPS present in Horner's syndrome

Answer 34

ptosis (drooping upper eyelid)

Question 35

what is the most superior muscle of the orbit

Answer 35

LPS

Question 36

what is the second most superior muscle of orbit, below LPS

Answer 36

superior oblique

Question 37

what direction of eye movement does contraction of superior oblique cause

Answer 37

inferior abduction (down and out)

Question 38

what is the third most superior muscle of orbit, below LPS and superior oblique

Answer 38

superior rectus

Question 39

what direction of eye movement does contraction of superior rectus cause

Answer 39

superior (elevation); slight adduction

Question 40

what direction of eye movement does contraction of inferior oblique cause

Answer 40

superior abduction (up and out)

Question 41

what direction of eye movement does contraction of inferior rectus cause

Answer 41

inferior (down); slight adduction

Question 42

what direction of eye movement does contraction of lateral rectus cause (clinical test)

Answer 42

abduction

Question 43

what direction of eye movement does contraction of medial rectus cause (clinical test)

Answer 43

adduction

Question 44

how to clinically test between inferior rectus and superior oblique (both depress eye) - H test

Answer 44

get patient to adduct eye first, then depress, to test superior oblique; get patient to abduct eye first, then depress, to test inferior rectus

Question 45

how to clinically test between superior rectus and inferior oblique (both elevate eye) - H test

Answer 45

get patient to adduct eye first, then elevate, to test inferior oblique; get patient to abduct eye first, then elevate, to test superior rectus

Question 46

what is intorsion and extorsion

Answer 46

rotational movement by eye muscles

Question 47

4 nerves of orbit

Answer 47

optic (CN II), oculomotor (CN III), trochlear (CN IV), abducens (CN VI)

Question 48

what is the optic nerve made out of

Answer 48

ganglion cell axons from retina

Question 49

number of rami in oculomotor nerve

Answer 49

2

Question 50

what muscles does oculomotor nerve innervate

Answer 50

medial rectus, superior rectus, inferior rectus, inferior oblique, LPS

Question 51

what muscle does trochlear nerve innervate

Answer 51

superior oblique

Question 52

what muscle does abducens nerve innervate

Answer 52

lateral rectus

Question 53

where does trigeminal ganglion sit

Answer 53

Meckel's cave, lateral to pituitary gland (this sits below optic chiasm)

Question 54

3 branches of ophthalmic division of trigeminal nerve (V1)

Answer 54

frontal, lacrimal, nasociliary

Question 55

what sinus wall do these nerves pass through, before reaching orbit

Answer 55

cavernous sinus

Question 56

location of cavernous sinus

Answer 56

either side of sphenoid bone

Question 57

what is on each side of cavernous sinus

Answer 57

folds of dura

Question 58

what artery passes through cavernous sinus

Answer 58

internal carotid artery to supply anterior part of brain

Question 59

what nerve doesn't run in wall of cavernous sinus, and instead runs with internal carotid artery more medially

Answer 59

abducens nerve (V)

Question 60

4 nerve order in cavernous sinus wall (inferior to superior)

Answer 60

maxillary division of trigeminal nerve (V2), ophthalmic division of trigeminal nerve (VI), trochlear nerve (IV), oculomotor nerve (III)

Question 61

outcome if cavernous sinus thrombosis or infection

Answer 61

damage to nerves

Question 62

2 branches of frontal branch of V1 (ophthalmic division of trigeminal nerve), and location where it supplies sensory innervation to skin

Answer 62

supratrochlear, supraorbital (forehead through supraorbital foramen)

Question 63

3 branches of nasociliary branch of V1 (ophthalmic division of trigeminal nerve)

Answer 63

branch to ciliary ganglion, ethmoidal, infratrochlear

Question 64

location of ciliary ganglion

Answer 64

just behind globe of eye

Question 65

ANS division of ciliary ganglion

Answer 65

PSNS

Question 66

where are preganglionic fibres of ciliary ganglion located

Answer 66

in inferior ramus of oculomotor

Question 67

where are postganglionic fibres of ciliary ganglion located

Answer 67

in short ciliary nerves

Question 68

what 2 muscles do ciliary ganglion innervate

Answer 68

sphincter pupillae and ciliary muscle

Question 69

which artery supplies blood to orbital

Answer 69

ophthalmic artery

Question 70

what 6 things does ophthalmic artery specifically supply blood to

Answer 70

central artery of retina, muscular, ciliary, lacrimal, supratrochlear, supraorbital

Question 71

2 ophthalmic veins, and what they drain back into

Answer 71

superior (cavernous sinus; potential route of infection), inferior (pterygoid plexus; not into cranial cavity)