Pediatric emergency medicine trisk 3294 3294

FIGURE 107.3 Mechanism of blowout fracture In a sagittal view, a ball is shown striking the eye, deforming it, and causing increased pressure of the intraorbital contents The periorbital fat is forced through the floor of the orbit Retropositioning of the eye (enophthalmos), lowering of the eye, and extraocular muscle entrapment can result In children, the floor of the orbit is relatively flexible Consequently, it may fracture in a linear pattern that snaps back to create a “trapdoor” fracture In adults, the floor of the orbit is thick and more likely to shatter when exposed to force If the inferior rectus muscle is entrapped in the fracture gap in the floor of the orbit, voluntary upward gaze may be limited Thin-cut coronal CT is especially valuable in detection of orbital blowout fractures and extraocular muscle entrapment The presence of entrapment is an indication to operate on a blowout fracture on an urgent basis A thorough ophthalmologic examination is warranted in all patients with orbital fractures because of the high likelihood of associated eye injuries In particular, vision should be assessed because decreased visual acuity may be an early sign of a retrobulbar hemorrhage, or injury to the optic nerve or eye itself A retrobulbar hemorrhage can cause compression of the central retinal artery, which can threaten vision to the affected eye if not surgically decompressed The type of eye and orbit injuries varies on the basis of the object and mechanism involved Typically, a low-impact mechanism with a small object will result in injuries to