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Frontal process (zygomatic bone)

The frontal process of the zygomatic bone is a vertical bony projection on the superior-medial aspect of the zygoma that articulates with the frontal bone, lacrimal bone, and maxilla. It contributes to the lateral wall and margin of the orbit, forming part of the orbital rim and providing structural support for the orbit and cheek. The frontal process is triangular or quadrangular in cross-section, tapering superiorly as it joins the frontal bone. Its anterior surface contributes to the contour of the zygofrontal region, while the posterior surface forms part of the lateral orbital wall, housing attachments for periorbital soft tissues and ligaments. Its size and angulation are variable, influencing both aesthetic and functional aspects of the midface.

Synonyms

  • Zygomatic frontal process

  • Frontozygomatic process

  • Superior-medial process of zygoma

Function

  • Forms the lateral margin of the orbit

  • Provides articulations with frontal, lacrimal, and maxillary bones

  • Serves as attachment for periorbital ligaments and soft tissues

  • Contributes to midfacial contour, orbital integrity, and lateral orbital stability

MRI Appearance
T1-weighted images:

  • Appears as a linear hypointense bony structure

  • Surrounded by hyperintense subcutaneous and periorbital fat, which provides natural contrast

  • Fractures or lesions appear as disruption of the normal low-signal continuity or abnormal signal within adjacent marrow

T2-weighted images:

  • Bony frontal process remains hypointense, while adjacent soft tissues or marrow edema appear hyperintense

  • Useful for evaluating trauma, bone marrow edema, or inflammatory changes

STIR (Short Tau Inversion Recovery):

  • Fat suppression enhances visualization of marrow edema or soft tissue abnormalities

  • Normal bony process is low signal; fractures, edema, or tumors appear bright hyperintense

CT Appearance

  • The frontal process is a well-corticated, hyperdense bony projection forming part of the lateral orbital rim

  • Air-filled adjacent structures, such as the maxillary sinus, appear hypodense, providing natural contrast

  • Clearly visualized in axial, coronal, and sagittal planes for trauma assessment, orbital fractures, or preoperative planning

MRI images

Frontal process (zygomatic bone) mri axial image -img-00000-00000