Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

Chapter Four The Appendicular Skeleton 539
Fig. 4-84 A 4-year-old male Basenji with moderate anemia. The lateral
radiographs of the forelimbs reveal a generalized increase in density
(osteosclerosis) in all bones. Similar changes were present in the
hind limbs and ribs. Diagnosis: Erythrocyte pyruvate kinase deficiency
of Basenjis.
ANATOMICAL, CONGENITAL, DEVELOPMENTAL, IDIOPATHIC
C H O N D R O D Y S P L A S I A
Several inherited chondrodysplasias, conditions due to abnormal cartilage development,
have been described. These include dwarfisms of Alaskan Malamutes, English Pointers, and
Irish Setters as well as cats; chondrodysplasia of Great Pyrenees and Norwegian elkhounds;
endochondrodystrophy of English Pointers; osteochondrodysplasia in Bull Terriers and
Scottish Deerhounds; skeletal and retinal dysplasia in Labrador Retrievers and Samoyed
dogs; chondrodysplasia in a cat; pseudoachondroplasia in Poodles; and congenital epiphyseal
dysplasia in Beagles and Poodles. 346-366 In some breeds (e.g., English Bulldogs, Welsh
Corgis, Skye Terriers, and Basset Hounds) the deformity resulting from chondrodysplasia
is considered to be normal and desirable. However, in some individuals this can result in
such asymmetric growth between the radius and ulna that there is subluxation of the
radioulnar joints and resultant clinical signs (Fig. 4-85).
Alaskan Malamute Dwarfism. A mendelian recessive short-limbed dwarfism has been
described in Alaskan Malamute dogs. 353,354 The skeletal lesion was generalized and symmetric
and best demonstrated in the carpus of 4- to 12-week-old dogs (Fig. 4-86). The distal
ulnar and radial metaphyses were widened and irregular. The time of appearance and
the ossification of epiphyseal growth centers were delayed compared with normal Alaskan
Malamutes. Lateral deviation of the paw and stunted growth were observed.