title: Observations of sacrocaudal fusion in Greyhounds and other dogs.
abstract: OBJECTIVE
  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).
  
  
  CONCLUSIONS
  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.
authors.forename: Aiman H
authors.initials: AH
authors.lastname: Oheida
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Philip
authors.forename: Hung-Hsun
authors.initials: HH
authors.lastname: Yen
authors.affiliation: Dr. Helen Davies, The University of Melbourne, Faculty of Veterinary Science, Parkville, Melbourne, Victoria 3010, Australia, E-mail: h.davies@unimelb.edu.au.
authors.forename: Helen M S
authors.initials: HM
authors.lastname: Davies
mesh_terms: D000818:Animals; D002420:Cauda Equina / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D004285:Dogs / Q000033:anatomy & histology*; D015994:Incidence; D008159:Lumbar Vertebrae / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D011859:Radiography; D012189:Retrospective Studies; D012447:Sacrum / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D013045:Species Specificity
keywords: Greyhound; sacrocaudal fusion