The supratrochlear nerve is a branch of the

frontal nerve The frontal nerve is the largest branch of the ophthalmic nerve (V1), itself a branch of the trigeminal nerve (CN V). It supplies sensation to the skin of the forehead, the mucosa of the frontal sinus, and the skin of the upper eyelid. It may be a ...

, itself a branch of the ophthalmic nerve (CN V₁) from the trigeminal nerve (CN V). It provides sensory innervation to the skin of the

forehead In human anatomy, the forehead is an area of the head bounded by three features, two of the skull and one of the scalp. The top of the forehead is marked by the hairline, the edge of the area where hair on the scalp grows. The bottom of the fo ...

and the

upper eyelid An eyelid ( ) is a thin fold of skin that covers and protects an eye. The levator palpebrae superioris muscle retracts the eyelid, exposing the cornea to the outside, giving vision. This can be either voluntarily or involuntarily. "Palpebral" ...

Structure

Origin

The supratrochlear nerve is the smaller of the two terminal branches of the

(the other being the

supraorbital nerve The supraorbital nerve is one of two terminal branches - the other being the supratrochlear nerve - of the frontal nerve (itself a branch of the ophthalmic nerve (CN V1)). It exits the orbit via the supraorbital foramen/notch before splitting ...

). It arises midway between the base and apex of the orbit where the frontal nerve splits into said terminal branches.

Course

The supratrochlear nerve passes medially above the trochlea of the

superior oblique muscle The superior oblique muscle or obliquus oculi superior is a fusiform muscle originating in the upper, medial side of the orbit (anatomy), orbit (i.e. from beside the nose) which abducts, depresses and internally rotates the eye. It is the only e ...

. It then travels anteriorly above the

levator palpebrae superioris muscle The levator palpebrae superioris () is the muscle in the orbit that elevates the upper eyelid. Structure The levator palpebrae superioris originates from inferior surface of the lesser wing of the sphenoid bone, just above the optic foramen. It ...

. It exits the orbit through the supratrochlear notch or foramen. It then ascends onto the forehead beneath the

corrugator supercilii muscle The corrugator supercilii muscle is a small, narrow, pyramidal muscle of the face. It arises from the medial end of the superciliary arch; it inserts into the deep surface of the skin of the eyebrow. It draws the eyebrow downward and medially, p ...

and

frontalis muscle The frontalis muscle () is a muscle which covers parts of the forehead of the skull. Some sources consider the frontalis muscle to be a distinct muscle. However, Terminologia Anatomica currently classifies it as part of the occipitofrontalis muscl ...

. It finally divides into sensory branches. The supratrochlear nerve travels with the

supratrochlear artery The supratrochlear artery (or frontal artery) is one of the terminal branches of the ophthalmic artery. It arises within the orbit. It exits the orbit alongside the supratrochlear nerve. It contributes arterial supply to the skin, muscles and peri ...

, a branch of the

ophthalmic artery The ophthalmic artery (OA) is an artery of the head. It is the first branch of the internal carotid artery distal to the cavernous sinus. Branches of the ophthalmic artery supply all the structures in the orbit around the eye, as well as some ...

Branches

Before exiting the orbit, the supratrochlear nerve emits a descending branch to the

infratrochlear nerve The infratrochlear nerve is a branch of the nasociliary nerve (itself a branch of the ophthalmic nerve (CN V1)) in the orbit In celestial mechanics, an orbit (also known as orbital revolution) is the curved trajectory of an object such as ...

Function

The supratrochlear nerve provides sensory innervation to the skin and

conjunctiva In the anatomy of the eye, the conjunctiva (: conjunctivae) is a thin mucous membrane that lines the inside of the eyelids and covers the sclera (the white of the eye). It is composed of non-keratinized, stratified squamous epithelium with gobl ...

of the upper

eyelid An eyelid ( ) is a thin fold of skin that covers and protects an eye. The levator palpebrae superioris muscle retracts the eyelid, exposing the cornea to the outside, giving vision. This can be either voluntarily or involuntarily. "Palpebral ...

, and the skin of the inferomedial forehead. It may also provide sensory innervation to part of the

periosteum The periosteum is a membrane that covers the outer surface of all bones, except at the articular surfaces (i.e. the parts within a joint space) of long bones. (At the joints of long bones the bone's outer surface is lined with "articular cartila ...

of the

frontal bone In the human skull, the frontal bone or sincipital bone is an unpaired bone which consists of two portions.'' Gray's Anatomy'' (1918) These are the vertically oriented squamous part, and the horizontally oriented orbital part, making up the bo ...

Clinical significance

The supratrochlear nerve may be anaesthetised for

surgery Surgery is a medical specialty that uses manual and instrumental techniques to diagnose or treat pathological conditions (e.g., trauma, disease, injury, malignancy), to alter bodily functions (e.g., malabsorption created by bariatric surgery s ...

of parts of the

scalp The scalp is the area of the head where head hair grows. It is made up of skin, layers of connective and fibrous tissues, and the membrane of the skull. Anatomically, the scalp is part of the epicranium, a collection of structures covering th ...

. This can be used for small lesions of the scalp. It can also be used for more extensive injury to the scalp. It is often anaesthetised alongside the

supraorbital artery The supraorbital artery is a branch of the ophthalmic artery. It passes anteriorly within the orbit to exit the orbit through the supraorbital foramen or notch alongside the supraorbital nerve, splitting into two terminal branches which go on to f ...

Etymology

The supratrochlear nerve is named for its passage above the trochlea of the

Additional images

File:Slide1h.JPG, Supratrochlear nerve File:Slide1abaa.JPG, Extrinsic eye muscle. Nerves of orbita. Deep dissection. File:Slide4abab.JPG, Extrinsic eye muscle. Nerves of orbita. Deep dissection. File:Slide5abab.JPG, Extrinsic eye muscle. Nerves of orbita. Deep dissection. File:Slide6abab.JPG, Extrinsic eye muscle. Nerves of orbita. Deep dissection. File:Slide7abab.JPG, Extrinsic eye muscle. Nerves of orbita. Deep dissection.

References

External links

* * * () * () * http://www.dartmouth.edu/~humananatomy/figures/chapter_47/47-2.HTM {{Authority control Ophthalmic nerve