Blood Supply and Innervation of the Lacrimal System

Question 1

Which three arteries supply the nasolacrimal apparatus and which single artery supplies the lacrimal gland?

Answer 1

Nasolacrimal apparatus-

1. Angular (branch off facial artery from the external carotid)
2. infraorbital (branch off maximally artery from the external carotid)
3. Dorsalnasal arteries (branch off ophthalmic artery that anastomoses with the angular artery)

Lacrimal gland-
1. Lacrimal artery off the ophthalmic artery.

Question 2

Course of dorsonasal artery

Answer 2

Terminal branch of the ophthalmic
Courses near the medial wall of orbit and pierces the orbital septum.
Travels alongside nose and then anastomoses with the angular artery.

Question 3

Course of lacrimal artery

Answer 3

Direct branch off the ophthalmic artery after it enters the orbit.
Courses anteriorly, along the upper border of the lateral rectus
Supplies the lacrimal gland (before reaching orbital septum)
Continues on to pierce the orbital septum to enter the UL and LL as the lateral palpebral arteries.

Question 4

Sensory innervation of the lacrimal gland is by CN

Answer 4

V1. Ophthalmic division by the lacrimal nerve

Touch sensation

Question 5

Motor innervation of the lacrimal gland is by

Answer 5

Parasympathetic nerve fibers. This is because it is a gland, which is involuntary and apart of the autonomic NS.

Question 6

Motor innervation of horners muscle is by

Answer 6

CN 7, facial nerve. (THINK- Horner’s muscle is apart of orbicularis oculi, which is innervated by CN 7)

Temporal and zygomatic branches of facial nerve supplies horners.