Which orbital bones are prone to infection and fracture?
The medial wall of the orbit is in areas paper thin (0.2-0.4 mm in thickness). This area over the ethmoidal air cells (ethmoid bone shown in green #3 ) and green in the figure below is prone to infection and blow out fractures. Interestingly, the honeycomb structure of the ethmoid air cells seems to provide more protection than would be expected because the floor of the orbit, although thicker, is much more prone to the blow-out fracture. The blow-out fracture can occur by a mechanism in which intraorbital pressure is increased from blunt trauma. The floor of the orbit is composed of the maxillary bone, part of the zygoma and the palantine bone. In a blow out fracture the contents of the inferior orbital fissure are susceptible to entrapment and injury. The medial wall of the orbit at the lesser wing of the sphenoid is the thickest area; forming the optic canal (nerve).