CHA Lecture 7: The Orbit

Question 1

Where are the neuron cell bodies of CN 2?

Answer 1

retina

Question 2

Where does the neurons of CN2 (optic nerve) terminate?

Answer 2

lateral geniculate nucleus (LGN)

Question 3

What branch of the ophthalmic nerve loops around the trochlear nerve before it enters the superior orbital fissure?

Answer 3

meningeal branch of the ophthalmic nerve (CN V1)

Question 4

What are the terminal divisions of the ophthalmic n.?

Answer 4

1) meningeal branch
2) Supratrochlear n.
3) medial branch of the supraorbital n.
4) lateral branch of the supraorbital n.
5) lacrimal n.

Question 5

What is the ophthalmic nerve called after the lacrimal nerve branches off?

Answer 5

frontal n.

Question 6

If a person has an infection along their nasal-labial fold, why is this a potentially dangerous problem?

What is the path that the infection would take to create this problem?

Answer 6

1) because veins in the face do not have valves, allowing for the infection to track into the cavernous sinus and create a cavernous sinus THROMBOSIS
2) Facial vein –> superior ophthalmic vein –> cavernous sinus

Question 7

What are the anstamoses of the external carotid with the internal carotid a. around the orbit?
HINT: There are 3 major ones

Answer 7

1) Angular artery with dorsal nasal a. or supratrochlear a.
2) Supraorbital a. with facial branch of the superficial temporal a.
3) Inferior lateral palpebral a. with the transverse facial a.

Question 8

What are the branches of the opthalmic artery?

Answer 8

1) Lacrimal artery (with muscular branch, zygomatic branch)
2) lateral palpebral a. (terminal branch of lacrimal)
3) Dorsal nasal a. (terminal branch)
4) Supratrochlear a. (terminal branch)
5) Supraorbital a. (terminal branch)
6) Posterior ethmoidal a.
7) Anterior ethmoidal a.
8) posterior ciliary arteries (/multiple from ophthalmic artery and one from lacrimal artery).
9) Central retina a. (branches off of ophthalmic a. and vascularizes the optic nerve).