The zygoma, commonly known as the cheekbone, is a prominent bone of the human face. This paired, irregularly shaped bone gives the face its distinct contours and plays a significant role in facial structure. It contributes to the midface region and is an integral component of the skull, connecting with several other facial and cranial bones.
Anatomical Location of the Zygoma
The zygoma is situated at the upper and lateral part of the face, forming the prominence of the cheek. It is found just below each eye and extends laterally and upward towards the outer side of the eye.
This bone connects with four other bones: the frontal bone, maxilla (upper jawbone), temporal bone, and sphenoid bone. The temporal process of the zygomatic bone extends backward to meet the zygomatic process of the temporal bone, forming the zygomatic arch. This arch is a horizontal bar of bone located along the side of the head, in front of the ear.
The zygoma also forms part of the lateral wall and floor of the eye socket, or orbit. Its orbital surface contributes to the anterolateral portion of the orbital floor and the anterior part of its lateral wall. The bone helps define the orbital rim.
Key Functions of the Zygoma
The zygomatic bone acts as a protective shield for the delicate structures within the eye socket and contributes to the overall structural integrity of the face. Its robust nature helps it withstand forces, particularly those associated with chewing.
The zygoma is an attachment point for various facial muscles, including the masseter muscle. The masseter, a powerful muscle involved in chewing, originates from the zygomatic arch and the maxillary process of the zygomatic bone. This connection allows for the elevation and protrusion of the mandible, enabling actions like biting and speaking. The zygoma also supports muscles responsible for facial expressions, such as smiling and frowning.
Common Issues and Injuries Affecting the Zygoma
Due to its exposed position, the zygoma is frequently susceptible to injury, particularly fractures. Zygomatic fractures are among the most common facial bone injuries, often second only to nasal bone fractures. These injuries typically result from high-impact trauma, such as assaults, motor vehicle accidents, falls, or sports injuries.
Symptoms of a zygomatic fracture can include pain, swelling, and bruising around the cheek and eyelids. A noticeable flattening of the cheekbone or facial asymmetry may also occur. Individuals might experience numbness in the upper lip, nose, cheek, or lower eyelid due to potential infraorbital nerve injury.
Difficulty opening the mouth, known as trismus, can arise if the fractured bone affects the surrounding muscles or jaw movement. Double vision (diplopia) may also be a symptom, especially if the eye socket is involved. Diagnosis often involves clinical examination and imaging like X-rays or CT scans. Treatment approaches vary based on the fracture’s severity, ranging from observation for non-displaced fractures to surgical intervention with plates and screws for more complex cases to restore function and appearance.