Nasalis muscle

The nasalis is a sphincter-like muscle of the nose whose function is to compress the nasal cartilages. It is the muscle responsible for "flaring" of the nostrils. Some people can use it to close the nostrils to prevent entry of water when underwater.

Nasalis muscle
Muscles of the head, face, and neck. (Nasalis labeled at center left.)
Details
Origin	Maxilla
Insertion	Nasal bone
Artery	Superior labial artery
Nerve	Buccal branch of the facial nerve
Actions	Compresses bridge, depresses tip of nose, elevates corners of nostrils
Identifiers
Latin	musculus nasalis
TA	A04.1.03.009
FMA	46770
Anatomical terms of muscle

It consists of two parts, transverse and alar:

• The transverse part (compressor naris) arises from the maxilla, above and lateral to the incisive fossa; its fibers proceed upward and medially, expanding into a thin aponeurosis which is continuous on the bridge of the nose with that of the muscle of the opposite side, and with the aponeurosis of the Procerus. It compresses the nostrils and may completely close them.
• The alar part (dilator naris[1]) arises from the maxilla over the lateral incisor and inserts into the greater alar cartilage. Its medial fibres tend to blend with the depressor septi, and has been described as part of that muscle.

Like all the other muscles of facial expression, nasalis muscle is innervated by the seventh cranial nerve: the facial nerve.[2]