Infratrochlear nerve
Branch of the nasociliary nerve
From Wikipedia, the free encyclopedia
The infratrochlear nerve is a sensory branch of the nasociliary nerve (itself a branch of the ophthalmic nerve (CN V1)) in the orbit.[1] It courses along the medial wall of the orbit and exits near the medial angle of the eye beneath to the trochlea of superior oblique.[2] It provides sensory innervation to structures at the medial orbit including the skin of the medial eyelids, root of the nose, and parts of the lacrimal sac.[1]: 631, 783 This nerve is relevant in procedures involving the medial eyelid, lacrimal apparatus, and nasal root.[3]
| Infratrochlear nerve | |
|---|---|
Sensory innervation of the head. The infratrochlear nerve is seen in the green area, emerging from the orbit. | |
| Details | |
| From | Nasociliary nerve |
| Innervates | Skin of eyelids, conjunctiva, lacrimal sac, lacrimal caruncle, side of nose above medial canthus |
| Identifiers | |
| Latin | nervus infratrochlearis |
| TA98 | A14.2.01.035 |
| TA2 | 6214 |
| FMA | 52693 |
| Anatomical terms of neuroanatomy | |
Structure
The nasociliary nerve terminates by bifurcating into the infratrochlear and the anterior ethmoidal nerves. The infratrochlear nerve travels anteriorly in the orbit along the upper border of the medial rectus muscle and underneath the trochlea of the superior oblique muscle. It exits the orbit medially and divides into small sensory branches.[4][verification needed]
Distribution
The infratrochlear nerve provides sensory innervation to the skin of the eyelids, the conjunctiva, lacrimal sac, lacrimal caruncle, and the side of the nose superior to the medial canthus.[1]: 631, 783
Communications
The infratrochlear nerve receives a descending communicating branch from the supratrochlear nerve.[1]: 782
Etymology
The infratrochlear nerve is named after a structure it passes under. Infratrochlear means "below the trochlea". The term trochlea means "pulley" in Latin. Specifically, the trochlea refers to a fibrocartilaginous loop at the superomedial surface of the orbit called the trochlea, through which the tendon of the superior oblique muscle passes.[1]
Additional images
Nerves of the orbit. Seen from above. The infratrochlear nerve is labelled at the top left, and can be seen as a terminal branch of the nasociliary nerve, along with the anterior ethmoidal nerve.
