Nasalis muscle

Nasalis muscle

Nasalis muscle (highlighted in green)

The Nasalis muscle is one of the facial muscles that is primarily responsible for the "flaring" of the nostrils. It is found in the human face, specifically in the nose area. The muscle is divided into two parts: the transverse part (compressor naris) and the alar part (dilator naris).

Structure

The transverse part or compressor naris is a flat, broad muscle which arises from the maxilla, above and lateral to the incisive fossa. Its fibers pass upward and medially, crossing the dorsum of the nose, and are inserted into the skin near the midline. It compresses the nostrils and is the cause of the deepening of the nasal labial groove during intense facial expression.

The alar part or dilator naris is a delicate fasciculus, which arises from the upper part of the lateral nasal cartilage and is inserted into the skin of the ala of the nose. It dilates the nostril, pulling the ala of the nose upward and outward.

Function

The nasalis muscle allows for the flaring of the nostrils, an action that is part of the process of respiration. It also plays a role in facial expressions, contributing to expressions of anger, disgust, and surprise.

Clinical significance

Understanding the structure and function of the nasalis muscle is important in rhinoplasty, a type of plastic surgery that is performed on the nose. Surgeons need to be aware of the nasalis muscle in order to avoid damaging it during surgery, which could result in a loss of the ability to flare the nostrils.

See also

• Facial muscles
• Rhinoplasty
• Respiration