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Developmental variation in lumbosacropelvic anatomy of thoroughbred racehorses.
Abstract: To describe the incidence and types of gross osseous developmental variations and ages of physeal closure in the caudal portion of the thoracic and lumbosacral spine and the pelvis in a sample of Thoroughbred racehorses. Methods: Thoroughbred racehorses (n = 36) that died or were euthanatized at California racetracks between October 1993 and July 1994. Methods: Lumbosacropelvic specimens were collected, and all soft tissues were removed. The osseous specimens were visually examined. Results: Only 22 (61%) specimens had the expected number of 6 lumbar and 5 sacral vertebrae. Eight (22%) specimens had thoracolumbar transitional vertebrae, and 13 (36%) had sacrocaudal transitional vertebrae. Articular process asymmetries were present at 1 or more vertebral segments in 30 (83%) specimens. Intertransverse joints (2 to 4 pairs/specimen) were bilaterally distributed in the caudal portion of the lumbar spine and the lumbosacral joint in 31 (86%) specimens. Five (14%) specimens had asymmetric distribution of the intertransverse joints. Intertransverse joint ankylosis was found in 10 (28%) specimens. Lumbosacral vertebral body physeal closure occurred between 4.9 and 6.7 years of age; pelvic physeal closure occurred between 5.2 and 5.8 years of age. Iliac crest and ischial arch epiphyseal formation was evaluated, using a grading system, and fusion to the underlying bone occurred at 7.2 years and 5.4 years of age, respectively. Conclusions: Numerous vertebral anatomic variations were commonly found in a sample of Thoroughbred racehorses. Conclusions: Normal anatomic variations and ages of skeletal maturity need to be considered in clinical evaluation of the equine spine and pelvis for differentiation from pathologic findings.
Publication Date: 1997-11-05 PubMed ID: 9328659 The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research paper analyzes the appearance and types of developmental variations in the bone structure in the lower part of the spine and pelvis in Thoroughbred racehorses. The study findings reveal that these anatomical variations are common, and their understanding is crucial for distinguishing between normal and potentially harmful conditions.
Research Methodology
- The research was conducted on 36 Thoroughbred racehorses that died or were euthanized at California racetracks between October 1993 and July 1994.
- The lower part of the spinal and pelvic bone specimens (lumbosacropelvic specimens) were collected, and all soft tissues were removed.
- The specimens were then visually examined to identify any developmental differences.
Key Findings
- Only 22 (61%) specimens had the expected number of 6 lumbar (lower back) and 5 sacral (located at the base of the lower back) vertebrae.
- Eight (22%) specimens showed thoracolumbar transitional vertebrae (a condition where there are variations in the number of vertebrae between the thoracic and lumbar regions of the back).
- Articular process asymmetries (unequal development of a joint’s surface) were found at one or more vertebral segments in 30 (83%) specimens.
- Intertransverse joints (joints that occur between transverse processes of the vertebra) ranging between 2 to 4 pairs per specimen, were found in the caudal (tail end) portion of the lumbar spine and the lumbosacropelvic joint in 31 (86%) specimens.
- Lumbosacral vertebral body physeal (growth region in the bones) closure occurred between 4.9 and 6.7 years of age, and for the pelvic region, it occurred between 5.2 and 5.8 years of age.
- Evaluation of the iliac crest (uppermost edge of the pelvis) and ischial arch (part of the pelvic structure) epiphyseal (growth region) formation revealed that their fusion to the underlying bone occurred at ages 7.2 years and 5.4 years respectively.
Conclusion
- The research found that numerous anatomic variations were common in the sample of Thoroughbred racehorses studied.
- Understanding these normal anatomic variations and the ages at which different aspects of skeletal development mature is essential in clinical evaluations of the equine spine and pelvis, to effectively differentiate between normal and potentially pathological conditions.
Cite This Article
APA
Haussler KK, Stover SM, Willits NH.
(1997).
Developmental variation in lumbosacropelvic anatomy of thoroughbred racehorses.
Am J Vet Res, 58(10), 1083-1091.
Publication
Researcher Affiliations
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, Davis 95616, USA.
MeSH Terms
- Aging / physiology
- Animals
- Epiphyses / anatomy & histology
- Female
- Horses / anatomy & histology
- Lumbar Vertebrae / anatomy & histology
- Male
- Pelvic Bones / anatomy & histology
- Sacrum / anatomy & histology
- Spine / physiology
- Tail / anatomy & histology
- Thoracic Vertebrae / anatomy & histology
Citations
This article has been cited 5 times.- Scilimati N, Angeli G, Di Meo A, Dall'Aglio C, Pepe M, Beccati F. Post-Mortem Computed Tomographic Features of the Most Caudal Lumbar Vertebrae, Anatomical Variations and Acquired Osseous Pathological Changes, in a Mixed Population of Horses. Animals (Basel) 2023 Feb 19;13(4).
- Spoormakers TJP, Veraa S, Graat EAM, van Weeren PR, Brommer H. A comparative study of breed differences in the anatomical configuration of the equine vertebral column. J Anat 2021 Oct;239(4):829-838.
- Galis F, Carrier DR, van Alphen J, van der Mije SD, Van Dooren TJ, Metz JA, ten Broek CM. Fast running restricts evolutionary change of the vertebral column in mammals. Proc Natl Acad Sci U S A 2014 Aug 5;111(31):11401-6.
- Patricio CR, Winter GHZ, Garbade P. Spinal articular dysfunction is common in athletic horses. Equine Vet J 2025 Sep;57(5):1357-1362.
- Covasa CT. Transitional, fused and/or supernumerary vertebrae in the lumbosacrocaudal region of the spine - A reality in many domestic mammals. Vet Med (Praha) 2024 May;69(5):156-168.
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