Pelvic ring anomaly at the caudal end of the sacroiliac joint in the dog

The pelvic ring-anomaly (PRA) is a bony alteration at the caudal end of the sacrum. Its frequency and the degree of its expression was studied in 5563 X-ray pictures of dogs of the breeds Boxer, Bernese Mountain Dog and St. B ernhard. The frequency in the Boxer with 14% was significantly higher as in the other breeds, and in this breed a sex disposition for bitches did exis t. An age related significant accumulation for PRA was seen in the dogs wit h an age up to 17 months. Further it was shown that PRA at the left side of the pelvis in the Boxer and St. Bernhard is more often than at the right s ide. PRA occurs move often at one side than at both sides. The etiology is unknown, and the combination of PRA with hip dysplasia or lumbosacral trans itional vertebrae is unclear.