The patient/client is sitting (or standing) and either facing a mirror or facing the person who will demonstrate flaring the nostrils. After showing a picture or demonstrating the flaring, ask the patient/client to flare the nostrils. With the muscle relaxed initially and with permission, gently place one or two fingers on the inferolateral aspect of the nose of the patient/client and ask the person to flare the nostrils. Ask the person to relax and repeat these motions if necessary. If permission is not granted, then observe as the person flares the nostrils, relaxes and then flares them again.

This video demonstrates palpation of the alar (dilator) part of the nasalis. This muscle is palpated only after muscle activation for better viewing. The correct technique of palpation of the muscle includes the sequence of muscle activation, relaxation of the muscle, placement of the fingers on the muscle before the muscle is activated, activation of the muscle, and relaxation of the muscle.

The whole nasalis muscle controls the position of the alar cartilages of the nose. The alar (dilator) portion of the nasalis muscle flares the nostrils, drawing the cartilage of the alae of the nose laterally to open the nostrils. This action occurs with deep inspiration during strenuous exercise. This muscle functions with the transverse part of the nasalis (compressor naris), which compresses the superior portion of the nose and therefore assists in flaring. The nasalis may function with the levator labii superioris alaeque nasi muscle if the sides of the nose are pulled upward or the depressor septi muscle, if the sides of the nose are pulled downward as the nostrils are flared.

In the VH Dissector, the alar or dilator part of the nasalis is simply called the nasalis.