Zygoma malposition

Untreated or undertreated zygoma fractures, with or without orbital involvement are common causes of residual midface deformities.

The fractured zygomatic bone is usually displaced posteriorly, laterally and inferiorly in the acute situation resulting in a significant orbital volume enlargement.

Lack of adequate 3 dimensional reduction of a zygoma fracture is the most common etiology of residual orbitozygomatic deformities.

The following clinical features may be present in different degrees:

• Depression of the malar eminence
• Enophthalmos

• Midface widening
• Inferior displacement of the lateral canthus
• Cheek ptosis

Posttraumatic enophthalmos (posterior axial globe displacement) is mainly related to orbital volume enlargement.

Enophthalmos may be associated with hypophthalmos (inferior globe displacement). The hypophthalmos is caused by the inferior displacement of the orbital floor at the level of the globe equator.

Medial displacement of the fractured zygoma produces a different deformity with midfacial narrowing and proptosis (exophthalmos, due to a reduced orbital volume).

Associated orbital floor and/or medial wall defects may enlarge orbital volume additionally resulting in a more severe enophthalmos.