Zygomaticus major muscle

The zygomaticus major is a prominent muscle of facial expression, positioned obliquely across the cheek. It is primarily responsible for elevating the angle of the mouth,

Anatomical details

1. Origin

From the lateral surface of the zygomatic bone, near its temporal process.

2. Insertion

Into the angle (corner) of the mouth, blending with fibres of the orbicularis oris, risorius, and levator anguli oris muscles.

Innervation

• Buccal branch of facial nerve

• Zygomatic branch of facial nerve

Blood supply

• Superior labial branch of facial artery

Actions

• Functionally, the zygomaticus major muscle is a key elevator of the mouth corner during voluntary and emotional smiling.

• It acts synergistically with the:

  • Zygomaticus minor (elevates the upper lip).

  • Levator anguli oris (raises the mouth corner vertically).

  • Orbicularis oris (modulates lip tension during smiling).

Relations

The zygomaticus major muscle lies:

• Superficial to the buccal fat pad and buccinator muscle.

• Inferior and lateral to the zygomaticus minor.

• Superior to the risorius.

• Medially, the fibres of zygomaticus major muscle blend at the modiolus (corner of the mouth).