Blowout Fracture of the Orbit

• Isolated fractures, most commonly of the orbital floor
• The cause is sudden, direct, blunt trauma in the form of a blow to the orbit with increase in intraorbital pressure
• The orbital rim is relatively strong so force is transmitted to the weakest parts of the orbit which “blow-out”
• Orbital floor which is the superior boundary of the maxillary sinus, or
• Medial wall (the thin lamina papyracea) which is the lateral boundary of the ethmoid sinus
• The nasal bone is also frequently fractured
• The cause is usually a large object such as baseball, fist, automobile accidents, tennis ball and kick

• Pain and tenderness
• Diplopia on upward gaze
• Due to entrapment of the inferior rectus and sometimes the inferior oblique muscles
• Enophthalmos
• Usually following initial swelling and proptosis
• Patient reports feeling of pressure in orbit when attempting to blow nose
• Facial anesthesia due to entrapment of the infraorbital nerve
• Epistaxis

• CT of the facial bones is the imaging study of choice
• Orbital emphysema
• Fracture of the floor or medial wall of the orbit
• Depression of the fracture fragment(s)
• Soft-tissue mass extending into the maxillary sinus
• Complete or partial opacification of the ipsilateral maxillary sinus from hemorrhage or edema

• Requirement for, timing of and method used for reconstruction of orbital floor is controversial
• Surgical repair, when performed, usually occurs after swelling has subsided
• If the diplopia does not resolve spontaneously
• Severe enophthalmos (>2mm)
• Large fractures (50% or more of floor)
• Consists usually of resection of periosteum and repair of hole using either bone graft, plate or synthetic material such as Teflon
• Long-standing entrapment can lead to vision impairment and enophthalmos

Blowout fracture of the orbit . Reformatted coronal CT of the facial bones demonstrates a fracture of the floor of the left orbit (white arrow) associated with orbital emphysema (blue arrow). A portion of the inferior rectus muscle (solid red arrow) projects into the maxillary sinus below (see normal opposite side--broken red arrow). There is blood in the maxillary sinus (white arrow).
For this same photo without the arrows, click here

Blowout fracture of the orbit . Reformatted coronal CT of the facial bones demonstrates a fracture of the floor of the left orbit (red arrow) with a depressed fragment protruding into the left maxillary sinus (white arrow). A portion of the inferior rectus muscle (yellow arrow) projects into the maxillary sinus below.
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