Sunday, October 11, 2009

Blow out fractures



Blow out fractures are fractures that are caused by a blunt force applied to the orbit. The fracture usually occurs within the orbital floor because it is the thinnest part of the orbital wall. Hemorrhaging of blood into the sinus cavity is evidence of a fracture in the floor of the orbit. Orbital emphysema may also be another side effect of this fracture. It is due to the leakage of air into the sinus cavity (usually occurs within the ethmoid sinuses).

One of the fractures that I find the most interesting is called a tripod fracture or a zygomaticomaxillary fracture. This type of fracture basically separates the zygomatic bone from the frontal and maxillary bone leaving a triangle shape, hence the name. Not only does this fracture sometimes cause facial deformity and the patient must have surgery, it may also cause an impingement on the optic canal. Patients may also complain of difficulty eating or blowing their nose. The diagram on the bottom and the picture on the 3-D image on the top are examples of tripod fractures.

A few years ago a patient got in a fight and was punched in the face several times and came in to the hospital to be evaluated. The ER doctor ordered a general facial bone series, but because plain radiographs were not sufficient enough, he was sent to have a CT scan done. He was given a diagnosis of a left tripod fracture and a fracture of the nasal bone.

References:

http://www.rad.washington.edu/academics/academic-sections/msk/teaching-materials/online-musculoskeletal-radiology-book/facial-and-mandibular-fractures

Eisenberg, Ronald M.D., J.D., F.A.C.R. & Johnson, Nancy, B.A., RT(R) (CV) (CT) (QM).
3rd Ed. 2003. Nervous System. Woodard, Linda Eds. Comprehensive Radiographic
Pathology
. (pp 322-323). Missouri: St. Louis.

radiology.uiowa.edu/downloads/

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