Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

546 Small Animal Radiolo g y and Ultrasono graphy
A
B
Fig. 4-91 An 11-month-old female Collie with a history of recurrent
shifting leg lameness. A, The density and cortical thickness of
the humerus are increased. B, There is a marked increase in
medullary and cortical density involving right and left radii. The
medullary canal is obliterated. There is no soft-tissue swelling. A linear
radiolucency is noted crossing the radius at the junction at the
proximal and middle thirds (arrow). There is slight deformity of the
radial outline at this point. This is a pathologic fracture. The growth
plates are open and are unaffected. The density of the metacarpal
bones appears increased although the carpal bones are spared. C,
There is thickening of the right femoral and tibial cortices with an
increased bony density in the medullary canal of these bones. The
fibula also appears dense. There is no evidence of soft-tissue swelling.
Diagnosis: Osteopetrosis with a pathologic fracture of the radius.
C