Composition and morphologic features of the interosseous muscle in Standardbreds and Thoroughbreds.
Abstract: Suspensory ligaments (SL) from 32 Thoroughbreds and 32 Standardbreds were collected to evaluate the variation in muscle content with respect to age, breed, sex, limb, and use. Six transverse sections, each 3 to 5 mm thick, were obtained from each SL. Four sections were taken from the body of the SL and 1 from the midportion of each branch. Sections were stained with van Gieson picric acid-fuchsin solution, then photographed, and black-and-white slides were made from the processed negatives. The transverse-sectional area of the SL and the contained muscle were determined by use of a computer with a color monitor and a digitizing device with its associated software. The percentage of muscle was then calculated for each section, for the entire ligament, and for each horse. Results were analyzed by multiple-regression analysis and Duncan multiple-range test, using the General Linear Model of SAS. Standardbreds had 40% more muscle in their SL than did Thoroughbreds. There was no significant difference in the percentage of SL muscle among sex, age, use, individual limb, or forelimb vs hind limb. For Standardbred horses, females had significantly greater muscle area content than intact males. Also, hind limb muscle area content was significantly greater than forelimb muscle content. Thoroughbred horses between 2 and 10 years of age not in training had significantly more muscle content than horses of the same age not in training. The reasons for these differences remain unclear.
Publication Date: 1991-01-01 PubMed ID: 2021241
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- Comparative Study
- Journal Article
Summary
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The study investigated the differences in muscle content within the suspensory ligament (SL) between Standardbreds and Thoroughbreds, considering factors such as breed, age, sex, and use of the horse. The results showed that Standardbreds had 40% more muscle in their SL than Thoroughbreds, with differences between sexes and limb usage within each breed.
Methodology Used
- The SLs from 32 Thoroughbreds and 32 Standardbreds horses were collected. The sample study examined variations in muscle content according to age, breed, sex, limb, and use of the horse.
- Six transverse sections of each SL were stained, photographed and slides were made.
- A computer with associated software was used to calculate the muscle percentage in the SL for each section, the entire ligament, and for each horse.
- The data collected were analyzed using multiple-regression analysis and Duncan multiple-range test.
Key Findings
- Standardbreds had 40% more muscle in their SL than Thoroughbreds. No significant differences were found in the percentage of SL muscle when considering sex, age, use, individual limb, or forelimb versus hind limb in general.
- In the case of Standardbreds, female horses had a significantly larger muscle area content than intact males. The hind limb muscle content was also significantly larger than in the forelimb.
- For Thoroughbred horses aged between 2 and 10 years, those not in training had more muscle content than those of the same age that were not in training.
Implications and Conclusion
- The results showed that there are variations in the muscle content in the SL between Thoroughbreds and Standardbreds, and these differences may be significant in determining the athletic capabilities of these breeds.
- Sex and use of limb may also contribute to the overall muscle quantity in Standardbreds.
- Among Thoroughbreds, age and training may play a crucial role in muscle content.
- The reasons behind these differences provide a path for future study as they remain unclear.
Cite This Article
APA
Wilson DA, Baker GJ, Pijanowski GJ, Boero MJ, Badertscher RR.
(1991).
Composition and morphologic features of the interosseous muscle in Standardbreds and Thoroughbreds.
Am J Vet Res, 52(1), 133-139.
Publication
Researcher Affiliations
- Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois, Urbana 61801.
MeSH Terms
- Animals
- Forelimb / anatomy & histology
- Hindlimb / anatomy & histology
- Horses / anatomy & histology
- Horses / classification
- Ligaments / anatomy & histology
- Male
- Muscles / anatomy & histology
- Species Specificity
Citations
This article has been cited 7 times.- Gerdes C, Morgan R, Terry R, Foote A, Smith R. Computed tomographic arthrography, gross anatomy and histology demonstrate a communication between synovial invaginations in the proximal aspect of the third interosseous muscle and the carpometacarpal joint in horses. Front Vet Sci 2022;9:958598.
- Mizobe F, Nomura M, Kato T, Nambo Y, Yamada K. Signal changes in standing magnetic resonance imaging of osseous injury at the origin of the suspensory ligament in four Thoroughbred racehorses under tiludronic acid treatment. J Equine Sci 2017;28(3):87-97.
- Spinella G, Britti D, Loprete G, Musella V, Romagnoli N, Vilar JM, Valentini S. Relative Echogenicity of Tendons and Ligaments of the Palmar Metacarpal Region in Foals from Birth to 4 Months of Age: A Longitudinal Study. PLoS One 2016;11(7):e0159953.
- Stanley RL, Fleck RA, Becker DL, Goodship AE, Ralphs JR, Patterson-Kane JC. Gap junction protein expression and cellularity: comparison of immature and adult equine digital tendons. J Anat 2007 Sep;211(3):325-34.
- Firth EC. The response of bone, articular cartilage and tendon to exercise in the horse. J Anat 2006 Apr;208(4):513-26.
- Freeman KD, Adams MN, Salinger AE, White NA 2nd, Barrett JG. Comparison of Two Surgical Techniques for the Treatment of Equine Hindlimb Proximal Suspensory Desmopathy. Animals (Basel) 2025 Sep 4;15(17).
- Guest DJ, Birch HL, Thorpe CT. A review of the equine suspensory ligament: Injury prone yet understudied. Equine Vet J 2025 Sep;57(5):1167-1182.
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