Nasalis (Transverse Part)

Facial Expression · Head & Neck

Nasalis (Transverse Part) belongs to the Facial Expression group of the Head & Neck. It arises from Maxilla, over the alveolar eminence of the canine tooth and attaches to Aponeurosis over the dorsum of the nose, continuous with the opposite side. Functionally, it compresses the nasal aperture (nostril). Its nerve supply is the Buccal branch of facial nerve (CN VII).

Origin, Insertion, Action & Nerve

Origin

Maxilla, over the alveolar eminence of the canine tooth

Insertion

Aponeurosis over the dorsum of the nose, continuous with the opposite side

Action

Compresses the nasal aperture (nostril)

Nerve

Buccal branch of facial nerve (CN VII)

Attachments explained

The Nasalis (Transverse Part) is defined first by where it attaches. Its origin is the more fixed anchor, usually the proximal or more stable end that stays put during contraction, while its insertion is the more mobile point that is pulled toward the origin when the muscle shortens.

Origin

Maxilla, over the alveolar eminence of the canine tooth

Insertion

Aponeurosis over the dorsum of the nose, continuous with the opposite side

Action & function

When the Nasalis (Transverse Part) contracts, it produces the following movement: Compresses the nasal aperture (nostril).

As part of the Facial Expression group of the Head & Neck, it works alongside neighbouring muscles to generate smooth, coordinated movement and to stabilise the structures it acts on.

Nerve supply & clinical relevance

The Nasalis (Transverse Part) receives its nerve supply from the Buccal branch of facial nerve (CN VII).

Because a muscle can only contract when its nerve is intact, injury to the Buccal branch of facial nerve can weaken or paralyse the Nasalis (Transverse Part), impairing the movements it normally produces (compresses the nasal aperture (nostril)). This is why knowing the innervation is central to localising nerve lesions in clinical practice.

How to study the Nasalis (Transverse Part) (the OIANS method)

OIANS stands for Origin, Insertion, Action and Nerve, the four facts that uniquely define every skeletal muscle. To learn the Nasalis (Transverse Part), work through them in order: picture its origin, trace the muscle to its insertion, reason out the action that shortening between those two points must create, then add the nerve that drives it.

Most students remember the Nasalis (Transverse Part) fastest by linking its action back to its attachments rather than memorising each fact in isolation. Once the origin and insertion make sense, the action usually follows logically.