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
References
1
Nickel R,
Schummer A,
Seiferle E.
et al. In The Anatomy of the Domestic Animals. Volume 1 The Locomotor System of the Domestic Mammals. Berlin: Verlag Paul Parrey; 1986. pg 31-33
2
Sisson S.
Carnivore osteology. In
Getty R.
editor Sisson and Grossman's The Anatomy of the Domestic Animals. 5th ed. Philadelphia: WB Saunders Co.; 1975. pg 1434-1436
4
Morgan JP.
Congenital anomalies of the vertebral column of the dog: a study of the incidence and significance based on a radiographic and morphologic study. J Am Vet Radiol Soc 1968; 9: 21-29.
6
Haussler KK,
Stover SM,
Willits NH.
Developmental variation in lumbosacropelvic anatomy of Thoroughbred racehorses. Am J Vet Res 1997; 58: 1083-1091.
9
Getty R.
Equine Osteology. In
Getty R.
editor Sisson and Grossman's The Anatomy of the Domestic Animals. 5th ed. Philadelphia: WB Saunders Co.; 1975. pg 263-266
10
Slijper EJ.
Comparative biologic-anatomical investigations on the vertebral column and spinal musculature of mammals. Amsterdam: North Holland Publishing Co.; 1946. pg 1-128
