Orbital Blowout Fracture

orbital blowout fracture

This 21 year old man was found lying on the ground with evidence of head and facial injuries. A coronal reformat image of a CT of the facial bones shows a depressed fracture of the floor of the right orbit. Extraconal intraorbital fat is herniating inferiorly through the fracture and the inferior rectus muscle is distorted and pulled inferiorly.

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.

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

Credit: Dr Bernard Ng, Dr Laughlin Dawes