Zygomaticus major muscle
Musculus zygomaticus major
Zygomaticus major is the strap-like facial muscle that runs from the cheekbone to the corner of the mouth and draws it into a smile.
At a glance
- English
- Zygomaticus major muscle
- Latin (TA2)
- Musculus zygomaticus major
- System
- Muscle
- Region
- Head
- Side
- Paired, left and right
About the zygomaticus major muscle
Zygomaticus major is one of the expression muscles of the face, lying in the cheek. It runs as a narrow band from the side of the cheekbone down and forwards to the angle of the mouth. It is the main muscle of the natural smile: when it shortens, the mouth corner is pulled upwards and outwards, and the cheek bunches up beneath the eye.
Its fibres begin on the outer surface of the zygomatic bone, near the upper edge of its temporal process, just in front of the junction with the zygomatic arch. They pass obliquely across the face, over the buccal fat and the facial vessels, to reach the modiolus, the dense knot of interlacing fibres beside the mouth where several lip muscles meet. There they blend with orbicularis oris and levator anguli oris. Zygomaticus minor lies just medial to it and works with it.
Like the other facial muscles, it is supplied by the facial nerve, here by its zygomatic and buccal branches, and it takes blood from the facial artery, chiefly through its superior labial branch. Paralysis of the facial nerve, as in Bell palsy, leaves the mouth corner drooping on the affected side and the smile lopsided, which makes this muscle a quick check of facial nerve function.
The muscle sometimes splits into two bundles that lie side by side, partly or wholly separate. This bifid form is thought to explain cheek dimples, since the skin dips where the gap tethers it. On average it can pull with a force of roughly two hundred grams. Because it is long and has a good blood and nerve supply, reconstructive surgeons can move it to restore tissue after injuries to the lips or to rebuild a smile.
Attachments, action and supply
- Origin
- Outer face of the zygomatic bone, near the top edge of its temporal process.
- Insertion
- Modiolus at the angle of the mouth, blending with orbicularis oris and levator anguli oris.
- Action
- Pulls the mouth corner upwards and laterally, as in smiling.
- Nerve supply
- Zygomatic and buccal branches of the facial nerve (CN VII).
- Blood supply
- Facial artery, mainly its superior labial branch.
Anthromica
See the zygomaticus major muscle where it really sits, with every layer of the body around it.
- Every layer, one body. Peel from muscle to bone, nerve, vessel and organ, and turn it any way.
- English and Latin. Every structure named the way your exam names it.
- Quiz until it sticks. Short drills on the structures you keep missing.
Free to start. No card.
