Orbit

Question 1

What 4 muscles insert onto the common tendinous ring?

Answer 1

All the rectus muscles: Sup, Inf, Lat, Med.

Question 2

What are the muscles in the upper and lower eyelids called? (consistently sympathetically innervated when awake)

Answer 2

superior and inferior tarsal muscles - Think Horner’s syndrome = droopy eyes

Question 3

What is Horner’s Syndrome and what are symptoms?

Answer 3

Loss of sympathetic innervation to the head. Droopy eyelids (tarsal plates) and constricted pupils (loss of dilation ability)
Also, bulging eyes cause tarsal muscles hold them in a little.

Question 4

Within the eye, what space do tears constitutively drain into?

Answer 4

conjunctival sac

Question 5

What is the medical term for droopy eyelids?

Answer 5

Ptosis

Question 6

Most of the extrinsic eye muscles function to move the globe. What is the exception and what does it do?

Answer 6

Levator Palpebrae Superioris- raises the eyelid.

Question 7

Are the muscles of the eye innervated by BE fibers?

Answer 7

NO! GSE!

Question 8

Name the neurovasculature that enters the orbit ABOVE the common tendinous ring.

Answer 8

Lacrimal Frontal (V1 branches)
Trochlear (CN VII)
Superior Opthalmic Vein.

LAZY FRENCH TARTS

Question 9

Name the neurovasculature that enters the orbit WITHIN the common tendinous ring.

Answer 9

Superior Occulomotor (CN III)
Nascilliary (V1)
Inferior Occulomotor (CN III)
Abducent (CN VI)

SIT NAKED IN ANTICIPATION

Question 10

What is the only structure that comes out below the tendinous ring?

Answer 10

Inferior Opthalmic Vein

Question 11

The frontal nerve terminates as 2 branches. Name them.

Which is more MEDIAL?

Answer 11

Supratrochlear and Supraorbital.

Supratrochlear is more medial.

Question 12

What runs with the nasocilliary nerve?

Answer 12

Opthalmic Artery

Question 13

What branches does the Opthalmic artery give off?

Answer 13

Anterior and Posterior Ethmoidal branches.

Remember the nasocilliary nerve does the same.

Question 14

What nerve innervates the Lateral Rectus?

Answer 14

Abducent (LR6)

Question 15

What nerve innervates the Superior Oblique?

Answer 15

Trochlear (SO4)

Question 16

The superior branch of the occulomotor nerve innervates what muscles?

Answer 16

The superior rectus and the legator palpebrae superioris.

Question 17

What muscles does the inferior branch of Occulomotor (CN III) innervate?

Answer 17

Medial, Inf rectus, and Inferior Oblique.

Question 18

The drug Pylocarpine does what?

Answer 18

(pupil constriction) because it is a parasympathetic mimetic drug.

Question 19

The drug Atropine does what?

Answer 19

Causes Myosis. (dilated pupil) because it blocks parasympathetic activation of constrictor muscles.

Question 20

GSA fibers to the globe are carried by what nerve?

What “helper” nerve carries these fibers from the nasocilliary nerve to the globe?

Answer 20

Nasocilliary (V1)- via the LONG CILLIARY NERVE

Question 21

Parasympathetic innervation to the orbit is carried by what nerve?

What ganglion do the preganglionics run to?

What nerve takes postganglionics to the orbit from the ganglion?

Answer 21

Occulomotor (III) carries parasympathatic innervation to the orbit. Preganglionics synapse in the ciliary ganglion and postganglionics reach the globe via the SHORT CILIARY NERVE.

Question 22

What is accommodation?

Answer 22

Walk into a dark room, pupils dilate. Walk into a bright room, pupils constrict.

Question 23

Belladonna is what?

Answer 23

A drug like Atropine that inhibits parasympathetic innervation to the eye. The pupils are highly dilated.

Question 24

What branch of the Opthalmic artery penetrates the Optic nerve? Why is it important?

Answer 24

The central retinal artery branches off Opthalmic and pierces the Optic nerve. It is the SOLE SUPPLY of blood to the retina. Lose it, go blind.

Question 25

What artery runs with the Lacrimal nerve?

Answer 25

Lacrimal Artery- branch of Opthalmic

Question 26

The opthalmic veins communicate with what important sites of venous drainage?

Answer 26

Pterygoid plexus and Cavernous sinus, angular vein of the face.

Question 27

What does Exopthalmos mean?

Answer 27

bulging eyes. As seen in Horner’s syndrome.