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An orbital blowout fracture is a traumatic deformity of the orbital floor or medial wall, typically resulting from impact of a blunt object larger than the orbital aperture, or eye socket. Most commonly the inferior orbital wall i.e. the floor is likely to collapse, because the bones of the roof and lateral walls are robust. Although the bone forming the medial wall is thinnest, it is buttressed by the bone separating the ethmoidal air cells. The comparatively thin bone of the floor of the orbit and roof of the maxillary sinus has no support and therefore it is the inferior wall that collapses mostly. So the medial wall blowout fractures are second most common, whereas superior wall i.e. the roof and lateral wall blowout fractures are uncommon & rare respectively. There are two broad categories of blowout fractures: open door, which are large, displaced and comminuted, and trapdoor, which are linear, hinged, and minimally displaced. They are characterized by double vision, sunken ocular globes, and loss of sensation of the cheek and upper gums due to infraorbital nerve injury.
In pure orbital blowout fractures, the orbital rim is preserved, while with impure fractures, the orbital rim is also injured. With the trapdoor variant, there is a high frequency of extra-ocular muscle entrapment, despite minimal signs of external trauma, a phenomenon referred to as a 'white-eyed' orbital blowout fracture. They can occur with other injuries such as transfacial Le Fort fractures or zygomaticomaxillary complex fractures. The most common causes are assault and motor vehicle accidents. In children, the trapdoor subtype are more common.
Surgical intervention may be required to prevent diplopia and enophthalmos. Patients that are not experiencing enophthalmos or diplopia, and that have good extraocular mobility can be closely followed by ophthalmology without surgery.