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 ...

, itself a branch of the

ophthalmic nerve The ophthalmic nerve (V1) is a sensory nerve of the face. It is one of three divisions of the trigeminal nerve (CN V). It has three branches that provide sensory innervation to the eye, the skin of the upper face, and the skin of the anterior scal ...

(CN V₁) from the

trigeminal nerve In neuroanatomy, the trigeminal nerve (literal translation, lit. ''triplet'' nerve), also known as the fifth cranial nerve, cranial nerve V, or simply CN V, is a cranial nerve responsible for Sense, sensation in the face and motor functions ...

(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 fore ...

and the upper eyelid.

Structure

The supratrochlear nerve is a branch of the

, itself a branch of the

(CN V₁) from the

(CN V). It is smaller than the

supraorbital nerve The supraorbital nerve is one of two branches of the frontal nerve, itself a branch of the ophthalmic nerve. The other branch of the frontal nerve is the supratrochlear nerve. Structure The supraorbital nerve branches from the frontal nerve mi ...

from the frontal nerve. It branches midway between the base and apex of the orbit. It passes 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 (i.e. from beside the nose) which abducts, depresses and internally rotates the eye. It is the only extraocular mus ...

. It then travels anteriorly above the levator palpebrae superioris muscle. It exits the orbit through the frontal notch in the superomedial margin of the orbit. It then ascends onto the forehead beneath the

corrugator supercilii muscle The corrugator supercilii muscle is a small, narrow, pyramidal muscle close to the eye. It arises from the medial end of the superciliary arch, and inserts into the deep surface of the skin of the eyebrow. It draws the eyebrow downward and media ...

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 then 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 peric ...

, 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 st ...

Function

The supratrochlear nerve provides sensory innervation to the skin of the lateral lower forehead, 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. The human eyel ...

, and the

conjunctiva The conjunctiva 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 goblet cells, stratified columnar epitheli ...

. It may also supply sensation to 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. Endosteum lines the inner surface of the medullary cavity of all long bones. Struc ...

of part of the

frontal bone The frontal bone is a bone in the human skull. The bone consists of two portions.'' Gray's Anatomy'' (1918) These are the vertically oriented squamous part, and the horizontally oriented orbital part, making up the bony part of the forehead, pa ...

of the

skull The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, t ...

Clinical significance

The supratrochlear nerve may be anaesthetised for surgery of parts of the

scalp The scalp is the anatomical area bordered by the human face at the front, and by the neck at the sides and back. Structure The scalp is usually described as having five layers, which can conveniently be remembered as a mnemonic: * S: The s ...

. 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.

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