Anterior Seg Anatomy

Question 1

what structure is a barrier for infections from the eyelids into the orbit & restricts fat from falling into the lid margin

Answer 1

orbital septum

Question 2

what is the passageway for nasociliary nerve, CN3, CN6, CN2, & ophthalmic artery

Answer 2

common tendinous ring (annulus of Zinn)

Question 3

what structure acts as a protective cover over EOM insertion into the sclera & separates the globe from orbital fat

Answer 3

Tenon’s capsule

Question 4

what are the structures in the nasolacrimal drainage system

Answer 4

lacrimal puncta → canaliculi → lacrimal sac → nasolacrimal duct → valve of Hasner

Question 5

what is the size of the canaliculi

Answer 5

10 mm ( 2mm vertical, 8mm horizontal)

Question 6

what lies within the fossa formed by maxillary & lacrimal bones & is located anterior to the orbital septum

Answer 6

lacrimal sac

Question 7

what is the size of the nasolacrimal duct

Answer 7

15mm long

Question 8

what prevents backflow of nasal fluids into the nasolacrimal duct

Answer 8

valve of Hasner

Question 9

what are the voluntary muscles of the orbit

Answer 9

EOMs & LPS

Question 10

what are the involuntary muscles of the orbit

Answer 10

Muller’s muscle

Question 11

what muscles are innervated by the superior branch of CN3

Answer 11

superior rectus, LPS

Question 12

what muscles are innervated by the inferior branch of CN3

Answer 12

medial rectus, inferior rectus, inferior oblique, Muller’s

Question 13

what are the three branches of the ophthalmic nerve (V1)

Answer 13

frontal, nasociliary, lacrimal

Question 14

which branch of V1 innervates the cornea

Answer 14

nasociliary

Question 15

what is the size of palpebral fissures

Answer 15

28-30mm wide, 9-10mm height

Question 16

what structure is composed of collagen fibrils that surround the meibomian glands

Answer 16

tarsal plates

Question 17

what provides rigidity to the eyelids

Answer 17

tarsal plates

Question 18

what is a mucus membrane w/ non-keratinized squamous epithelium?

Answer 18

conjunctiva

Question 19

what tissue maintains the shape of the globe

Answer 19

sclera

Question 20

what are the layers of the cornea

Answer 20

epithelium → Bowman’s → stroma → Descemet’s → endothelium

Question 21

which layers of the cornea cannot regenerate

Answer 21

Bowman’s & endothelium

Question 22

what is the corneal stroma composed of

Answer 22

collagen fibrils, keratocytes, ECM

Question 23

where are the stem cells of the cornea found

Answer 23

limbus

Question 24

what is the thickest layer of the cornea?

Answer 24

stroma

Question 25

what muscle originates at the common tendinous ring?

Answer 25

inferior rectus

Question 26

what muscle is innervated by the sympathetic nervous system?

Answer 26

muller's muscle

Question 27

what ganglion is located inside the orbit?

Answer 27

ciliary

Question 28

what is the average height of the palpebral fissure?

Answer 28

10 mm

Question 29

what travels adjacent to maxillary sinus through the nasolacrimal canal & terminates at the inferior meatus

Answer 29

nasolacrimal duct

Question 30

which branch of the nasociliary nerve innervates the conjunctiva, medial eyelids, lacrimal sac, caruncle, & side of nose A) infratrochlear B) long ciliary C) short ciliary

Answer 30

infratrochlear

Question 31

which branch of nasociliary nerve innervates the iris, corneal epithelium, anterior & middle corneal stroma & Muller's A) infratrochlear B) long ciliary C) short ciliary

Answer 31

long ciliary

Question 32

which nasociliary branch innervates the ciliary body & iris sphincter? A) infratrochlear B) long ciliary C) short ciliary

Answer 32

short ciliary

Question 33

what height of the palpebral fissure would be considered eyelid retraction?

Answer 33

> 12 mm

Question 34

the conjunctiva is composed of? which one contains goblet cells?

Answer 34

- epithelial layer → contains goblet cells | - stroma

Question 35

which tissue contains superficial & deep vascular networks that are visible through the conjunctiva?

Answer 35

episclera

Question 36

what layer is the attachment site for all EOMs?

Answer 36

sclera

Question 37

what is the average central thickness of the cornea? | average peripheral thickness?

Answer 37

- central → 540-560 microns | - peripheral → 710 microns

Question 38

what separates the anterior & posterior chambers?

Answer 38

iris

Question 39

where are blood vessels located in in the iris?

Answer 39

iris stroma