The Procerus is a small pyramidal slip of muscle deep to the superior orbital nerve, artery

Supra-orbital artery

-Course:It springs from the ophthalmic artery as that vessel is crossing over to the medial side of the optic nerve.It passes upward on the medial borders of the superior rectus muscle and levator palpebrae superioris, meeting the supraorbital nerve accompanies it between the roof of the orbit and...

 and vein

Supraorbital vein

The supraorbital vein begins on the forehead where it communicates with the frontal branch of the superficial temporal vein.It runs downward superficial to the Frontalis muscle, and joins the frontal vein at the medial angle of the orbit to form the angular vein.Previous to its junction with the...

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Origin and insertion

It arises by tendinous

Tendon

A tendon is a tough band of fibrous connective tissue that usually connects muscle to bone and is capable of withstanding tension. Tendons are similar to ligaments and fasciae as they are all made of collagen except that ligaments join one bone to another bone, and fasciae connect muscles to other...

 fibers from the fascia

Fascia

A fascia is a layer of fibrous tissue that permeates the human body. A fascia is a connective tissue that surrounds muscles, groups of muscles, blood vessels, and nerves, binding those structures together in much the same manner as plastic wrap can be used to hold the contents of sandwiches...

 covering the lower part of the nasal bone

Nasal bone

The nasal bones are two small oblong bones, varying in size and form in different individuals; they are placed side by side at the middle and upper part of the face, and form, by their junction, "the bridge" of the nose.Each has two surfaces and four borders....

 and upper part of the lateral nasal cartilage

Lateral nasal cartilage

The lateral cartilage is situated below the inferior margin of the nasal bone, and is flattened, and triangular in shape....

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It is inserted into the skin over the lower part of the forehead

Forehead

For the Arsenal striker see GervinhoIn human anatomy, the forehead is the fore part of the head. It is, formally, 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...

 between the two eyebrows on either side of the midline, its fibers merging with those of the Frontalis

Frontalis

Frontalis may refer to:* Crista frontalis, the frontal crest, a crest on the internal surface of the squama frontalis of the frontal bone* Frontalis muscle, a thin, quadrilateral fascia muscle located on the front of the head...

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Function

It helps to pull that part of the skin between the eyebrows downwards, which assists in flaring the nostrils.

It can also contribute to an expression of anger

Anger

Anger is an automatic response to ill treatment. It is the way a person indicates he or she will not tolerate certain types of behaviour. It is a feedback mechanism in which an unpleasant stimulus is met with an unpleasant response....

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Procerus is supplied by temporal and lower zygomatic branches from the facial nerve (a supply from the buccal branch has been described) . Its contraction can produce transverse wrinkles.