What sign may be seen on plain x-ray with a blowout fracture due to orbital fat herniating into the maxillary sinus?

The tear drop sign is associated with a blowout fracture of the orbital floor, specifically when orbital fat herniates into the maxillary sinus. This sign appears as a characteristic accumulation of soft tissue density within the sinus on plain x-ray or CT, resembling a teardrop shape. The herniation of fat demonstrates that there is a disruption of the orbital floor, which allows the orbital contents to move downward into the maxillary sinus due to pressure differences or trauma.

In context, the tear drop sign is significant because it serves as an indicator of severe orbital injury, and recognizing it can lead to prompt and appropriate management, which is crucial in preventing complications such as double vision, enophthalmos, or even ocular injury. Understanding this sign helps clinicians evaluate the extent of injury and determine the need for surgical intervention to repair the fracture and restore normal orbital anatomy.