Summary
Objectives: To describe the incidence and forms of nonpathological sacrocaudal fusion in racing
Greyhounds and compare them with those in a variety of other domestic dog breeds.
Methods: This retrospective observational study used archived anatomical specimens from 81
racing Greyhounds and 10 Beagles, and archived clinical radiographs from 81 non-Greyhound
dogs representing 37 other breeds. Dogs less than two years of age and dogs with evidence
of soft tissue or osseous pathology involving the sacrocaudal region were excluded.
The incidence of osseous sacrocaudal fusion (any type and complete fusion) was compared
between Greyhounds and all of the other dogs combined, using the Fisher's exact test.
Results: Sacrocaudal fusion of some type was found in 33 (41%) of 81 Greyhounds but in only
14 (15%) of 91 non-Greyhound dogs (p <0.01). Complete fusion (osseous fusion of vertebral
bodies and both transverse and articular processes) between the sacrum and the first
caudal vertebra was the most common form in Greyhounds, found in 27 (33%) of 81 Greyhounds,
but in only three (3.3%) of 91 non-Greyhound dogs (p <0.01).
Clinical significance: Sacrocaudal fusion appears to be more prevalent in Greyhounds than in other domestic
dog breeds and may be attributable to selection pressure for speed on a region of
the spine that is naturally prone to variation. Its significance for performance and
soundness requires further study.
Keywords
Greyhound - sacrocaudal fusion
