Head and neck muscles (chewing, facial, and throat muscles)

Zygomaticus Major

Musculus zygomaticus major

Origin

Zygomatic bone, anterior to the zygomaticotemporal suture

Insertion

Angle of the mouth, interweaving with the orbicularis oris muscle

Function

Pulls the corner of the mouth obliquely upward and laterally: the principal muscle of a genuine (Duchenne) smile

Innervation

Zygomatic and buccal branches of the facial nerve (CN VII)

Movement & chain

Pulls the corner of the mouth obliquely upward and laterally; the principal mimetic movement of a genuine (Duchenne) smile.

Palpation

Well palpable as an oblique band from the zygomatic bone to the corner of the mouth during a broad smile.

Clinical

Asymmetric smile in peripheral facial palsy largely results from failure of this muscle.

Segmental innervation

CN VII, motor.

In clinical practice

The primary 'smiling muscle'; neuromuscular retraining using EMG biofeedback to recover genuine emotional facial expression.

Region in the model

Head and neck muscles (chewing, facial, and throat muscles)