Procerus muscle

At a glance

English

Procerus muscle

Latin (TA2)

Musculus procerus

System

Muscle

Region

Head

Side

Paired, left and right

About the procerus muscle

The procerus, also known as the pyramidalis nasi, is a small muscle of facial expression lying over the top of the nose, between the inner ends of the eyebrows. It is a narrow, pyramid-shaped slip, and it sits in the midline region next to its partner, often blending with it. Its name comes from a Latin word meaning tall or drawn out, a reference to its long, slender form.

It arises by short tendinous fibres from fascia over the lower nasal bone and the top of the lateral nasal cartilage. From there it runs upwards over the root of the nose and ends in the skin of the lower forehead between the eyebrows, close to the midline. Its upper fibres merge with the medial edge of the frontalis, so the two are hard to separate. The supratrochlear nerves and vessels lie close by as they climb onto the forehead.

When it contracts it pulls the skin between the brows downwards, lowering the inner ends of the eyebrows and producing transverse wrinkles over the bridge of the nose. This is part of the expression of anger, concentration or distaste, and with the corrugator supercilii it helps to shade the eyes from strong light; it may also assist in flaring the nostrils. It is supplied by the facial nerve, mainly by the temporal branches and the lower zygomatic branches, although a contribution from the buccal branches has also been described, and its blood comes from the angular artery and the supratrochlear artery.

A persistent, involuntary furrowing of the procerus is one of the signs described in progressive supranuclear palsy, a degenerative brain disease, and is known as the procerus sign. More often the muscle is treated for cosmetic reasons: horizontal lines at the root of the nose and frown lines around the glabella can be softened by botulinum toxin, by cutting the muscle, or by dividing the nerve branches that supply it, though more than one branch may need to be cut.

Attachments, action and supply

Origin

Fascia over the lower nasal bone and the upper lateral nasal cartilage.

Insertion

Skin of the lower forehead between the eyebrows, blending with frontalis.

Action

Draws the skin between the brows down, making transverse wrinkles over the bridge of the nose.

Nerve supply

Temporal and lower zygomatic branches of the facial nerve (cranial nerve VII), sometimes with buccal branches.

Blood supply

Angular artery and supratrochlear artery.