On biomechanical properties of the sacroiliac joint in purebred dogs

Relative to the Yorkshire Terriers and Maltese dogs the mean expected sacro iliac joint load was calculated to be 1.4-1.6 times higher in other small b reeds and 1.7-2.7 times higher in large breeds. The statistically significa ntly different (p < 0.01, p < 0.001) and mechanically less efficient inclin ation angles of the wings of the sacrum in adult large breeds (especially G erman Shepherd Dogs) suggest even higher forces acting on their sacroiliac ligaments. Unlike the case in small breeds, the sacral auricular surface wa s concave in large dogs to improve interlocking between sacrum and ilium an d to reduce craniocaudal translation. An additional ossification center for ming the ventral aspect of the transverse process of the second sacral vert ebra was present in large breeds, occasionally in midsized and small, but n ever in toy breeds. This and the relationship between age and inclination a ngles of the wings of the sacrum in juvenile specimens indicate an affectio n of the three-dimensional modeling of the wings of the sacrum by formative stimuli such as body weight and locomotion.