Dilator naris anterior

The dilator naris anterior (Latin: musculus dilator naris anterior) is a muscle of facial expression that encircles the nostril and participates in widening it. It is classified as the nasal facial muscle.

Sometimes the dilator naris anterior and posterior are referred to as parts of the nasalis muscle. Together with the alar part of the nasalis, the dilator naris anterior may also function to prevent the collapse of the nasal valve during inspiration.

Origin

The dilator naris anterior originates from the upper lateral cartilage and alar portion of the nasalis muscle.

Insertion

The dilator naris anterior inserts into the skin of the nose at the lower margin of the lateral alar crus of the lower lateral (greater alar) cartilage.

Action

Upon contraction, the dilator naris anterior dilates the nostril.

Innervation

The dilator naris anterior muscle is innervated by the buccal branch of the facial nerve (CN VII).

Blood supply

The dilator naris anterior receives arterial blood supply from the branches of the facial artery.