Medial Blow Out Fracture

Medial blow out fracture

This patient suffered a direct blow to the left orbit during a motor vehicle accident some months earlier. This resulted in a medial blow-out fracture through the lamina papyracea, with extrusion of orbital fat, but no EOM entrapment.

An orbital blowout fracture is a fracture of one of the walls or floor of orbit with an intact orbital rim. It is the commonest orbital fracture, with orbital floor fractures more common than medial wall fractures. It is produced by a blow to the orbit which suddenly increases the intraorbital pressure, fracturing a portion of the orbital bony lining.

Complications of blowout fracture include enophthalmos due to increased globe volume, diplopia on vertical gaze due to tissue entrapment, and globe injury. Orbital emphysema or haemorrhage may occur. Injury to the inferior orbital nerve may cause facial numbness.

Indications for surgical repair include significant enophthalmos, significant diplopia, muscle entrapment, and large area fractures. Repair should be prompt to avoid longstanding complications.

For images of inferior and superior blow out fractures, please visit Radiopaedia.org here.

References:
1. Novelline et al. Pocket Radiologist: ER Trauma Top 100 Diagnoses. Amirsys 2004
2. www.eMedicine.com

Credit: Dr Frank Gaillard