Structure and Pathway
- Nasociliary nerve bifurcates into infratrochlear and anterior ethmoidal nerves.
- Infratrochlear nerve travels anteriorly in the orbit along the upper border of the medial rectus muscle.
- Infratrochlear nerve exits the orbit medially.
- Infratrochlear nerve passes underneath the trochlea of the superior oblique muscle.
Distribution of Sensory Innervation
- Infratrochlear nerve provides sensory innervation to the skin of the eyelids.
- Infratrochlear nerve provides sensory innervation to the conjunctiva.
- Infratrochlear nerve provides sensory innervation to the lacrimal sac.
- Infratrochlear nerve provides sensory innervation to the lacrimal caruncle.
- Infratrochlear nerve provides sensory innervation to the side of the nose superior to the medial canthus.
Communications
- Infratrochlear nerve receives a descending communicating branch from the supratrochlear nerve.
Etymology
- Infratrochlear nerve is named after the structure it passes under.
- 'Infratrochlear' means below the trochlea.
- 'Trochlea' refers to a fibrocartilaginous loop at the superomedial surface of the orbit.
- Trochlea is the passage for the tendon of the superior oblique muscle.
Additional Information
- Nerves of the orbit can be seen from above.
- Infratrochlear nerve is labeled as a terminal branch of the nasociliary nerve.
- Infratrochlear nerve is shown along with the anterior ethmoidal nerve.
The infratrochlear nerve is a branch of the nasociliary nerve (itself a branch of the ophthalmic nerve (CN V1)) in the orbit. It exits the orbit inferior to the trochlea of superior oblique. It provides sensory innervation to structures of the orbit and skin of adjacent structures.
| 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 | |
