Eye and Orbit 2

Question 1

7 bones that make up the orbit

Answer 1

frontal, maxilla, zygomatic, sphenoid, ethmoid, lacrimal, palatine

Question 2

why are the floor and medial wall of the orbit weaker

Answer 2

because there are sinuses on the other side

Question 3

what sit behind the eye occupying the rest of the orbit

Answer 3

fat

Question 4

what feature of someones eyes may suggest they are in starvation

Answer 4

sunken eyeballs (loss of fat behind eyes)

Question 5

what disease can cause hypertrophy of fat behind eyes

Answer 5

thyroid eye disease

Question 6

glands at eyelashes

Answer 6

sebacous glands secrete oily

Question 7

why is the tarsal plate needed

Answer 7

to prevent the eyelid from being scrunched up. palpebra and oculi would have a naturally scrunched up tone

Question 8

glands within the tarsal plate

Answer 8

meibomian glands

Question 9

structure that lies posterior to the tarsal plate

Answer 9

conjunctiva

Question 10

3 sections of conjunctiva

Answer 10

palperbral, superior/inferior fornix, ocular

Question 11

what structure on the front of the eye does the conjuctiva not cover and why

Answer 11

the cornea. conjunctiva is a very vascular membrane and vessels often leak, don’y want it affecting the quality of light passing through this transparent structure

Question 12

what is the conjunctiva

Answer 12

a thin vascular membrane covering the inside surface of the eyelids and sclera

Question 13

what does the conjunctiva look like over the sclera

Answer 13

transparent and containing blood vessels

Question 14

where is the lacrimal gland

Answer 14

in the superior orbit slightly lateral and quite anterior

Question 15

innervation of lacrimal gland

Answer 15

para-sympathetic, by facial nerve VII

Question 16

course of the tears/lacrimal fluid

Answer 16

secreted from gland through duct into conjunctival sac where it is spread across eye surface. Collected in medial corner and drained into the lacrimal sac by superior and inferior punctae. lacrimal sac drains into nasolacrimal duct which drains into the inferior meatus

Question 17

effect of blinking on lacrimal sac

Answer 17

orbicularis muscle pull on lacrimal sac opening it, creating a negative pressure to pull in fluid

Question 18

intrinsic muscles of eye

Answer 18

ciliaris muscle and dilator and constrictor pupillae

Question 19

innervation of ciliaris muscle and constrictor pupillae

Answer 19

III occulomotor (parasympathetic)

Question 20

innervation of dilator pupillae

Answer 20

sympathetic

Question 21

6 extrinsic muscles

Answer 21

lateral, medial, superior and inferior rectus and superior and inferior oblique

Question 22

little pulley of superior oblique

Answer 22

trochlea

Question 23

origin insertion of rectus muscle

Answer 23

annular fibrous ring at apex of orbit

Question 24

which is the only extrinsic muscle to originate from the front of the orbit

Answer 24

inferior oblique

Question 25

nerve supply of lateral rectus

Answer 25

abducent VI (as in abduct, like the action of the lateral rectus)

Question 26

nerve supply of superior, inferior, medial rectus and inferior oblique

Answer 26

oculomotor III

Question 27

nerve supply of superior oblique

Answer 27

trochlear IV

Question 28

which are the only two extrinsic muscles not to be innervated by III oculomotor

Answer 28

lateral rectus and superior oblique