Os zygomaticum

Os Zygomaticum (also known as the Zygomatic bone or Cheekbone) is a paired bone of the human skull. It articulates with the maxilla, the temporal bone, the sphenoid bone and the frontal bone. It is situated at the upper and lateral part of the face and forms the prominence of the cheek, part of the lateral wall and floor of the orbit, and parts of the temporal and infratemporal fossa. It presents a malar and a temporal surface; four processes, the frontosphenoidal, orbital, maxillary, and temporal; and four borders.

Structure

The os zygomaticum is roughly quadrangular in shape, and has three surfaces: orbital, temporal and anterior.

Orbital surface

The orbital surface forms part of the lateral wall and floor of the orbit. It is smooth and convex, and presents medially and posteriorly a rough, triangular area which articulates with the Maxillary bone and the Greater Wing of the Sphenoid.

Temporal surface

The temporal surface, directed posteriorly and medially, is concave, presenting medially a rough, triangular area for articulation with the Maxillary bone.

Anterior surface

The anterior surface forms the prominence of the cheek. It is subcutaneous and smooth, and crossed by a few oblique ridges, corresponding to the divisions between the masseteric fasciculi.

Clinical significance

Due to its position, the os zygomaticum can be easily fractured by blows to the face. Zygomatic complex fracture, also known as a tripod fracture, quadripod fracture, or trimalar fracture, is a fracture of the zygomatic bone.

See also

• Zygomatic arch
• Zygomatic process
• Zygomatic complex fracture