Myrtiformis muscle

Myrtiformis muscle (MM) (also known as depressor alae nasi) is one of the muscles of the nose, a subset of the muscles of facial expression.

Terminology

Myrtiformis is often omitted from classic anatomy tomes. Some texts describe this muscle as two separate components, the medial fibers forming the depressor septi nasalis muscle, and the lateral fibers forming depressor alae nasi .

Summary

• origin: maxilla
• insertion: floor of the nostril
• innervation: facial nerve (VII)
• action: depresses and flares the nostril

Gross anatomy

Origin

• arises from the myrtiform fossa of the maxilla, superior to the lateral incisor and canine, and ascends to its insertion site

Insertion

• anterior labial fibers: insert into the upper lip
• posterior nasal fibers: insert into the nostril floor, specifically the nostril sill and base of the columella

​​Arterial supply

• facial artery

Venous drainage

• facial vein

Innervation

• buccal nerve (branch of facial nerve (VII))​

Action

• depresses and flares the nostril

Variant anatomy

Muscles of the nose vary in size between individuals and may be entirely absent .

History and etymology

Myrtiformis is derived from the Latin for 'shaped like myrtle berries' .