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Home / Equine Research Bank / Anat Histol Embryol / Histological Study of the Normal Proximal Third Interosseus ...
Anatomia, histologia, embryologia2025; 54(4); e70059; doi: 10.1111/ahe.70059

Histological Study of the Normal Proximal Third Interosseus Muscle Enthesis in the Equine Pelvic Limb.

Abstract: In human medicine, the enthesis, or tendon-to-bone insertion, is generally considered a linked entity or 'enthesis organ' and plays a crucial biomechanical role. This study aimed to histologically assess the equine proximal third interosseus muscle (suspensory ligament) enthesis in 10 pelvic limbs from 7 horses. The area of the proximal third interosseus muscle enthesis was divided into 6 compartments based on post-mortem computed tomography and prepared for histology using haematoxylin/eosin and trichrome staining. The proximal third interosseus muscle enthesis showed a fibrocartilaginous nature. All adult entheses exhibited a characteristic four-layered structure consisting of ligament, uncalcified fibrocartilage, calcified fibrocartilage and bone. Juvenile specimens lacked clear layering, suggesting ongoing endochondral ossification. One or more smooth, regular tidemarks separated the uncalcified and calcified fibrocartilage, while the margins separating the ligament and bone from the fibrocartilage layer showed pronounced irregular interdigitations. Mean cellularity, fibrocartilage thickness and interdigitation size and shape varied among specimens. The fibrocartilaginous nature of the proximal third interosseus muscle enthesis in the equine pelvic limb supports the role of a stress dissipation mechanism and may have implications in the biomechanics and pathology of proximal third interosseus muscle enthesis injuries.
© 2025 Wiley‐VCH GmbH. Published by John Wiley & Sons Ltd.
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Publication Date: 2025-07-29 PubMed ID: 40728262DOI: 10.1111/ahe.70059Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

This research examines the specific part of a horse’s pelvic limb known as the ‘enthesis’ of the proximal third interosseus muscle (or suspensory ligament), aiming to provide a detailed understanding of its structure and potential biomechanical role. The study conducted a histological analysis on the limbs of 7 horses.

Study Methodology

  • The study focused on the enthesis, which is the point where tendons or ligaments attach to a bone, and in this case, it pertains to the proximal third interosseus muscle of equines.
  • The research involved 7 horses from which 10 pelvic limbs were gathered.
  • The enthesis area was divided into 6 compartments for enhanced analysis, facilitated by computed tomography used post-mortem.
  • Two types of staining were used to prepare the samples for histology, haematoxylin/eosin and trichrome staining.

Findings

  • The entheses in adult horsed showed a fibrocartilaginous nature and characteristic four-layered structure that entails ligament, uncalcified fibrocartilage, calcified fibrocartilage, and bone.
  • In contrast, juvenile samples lacked clear layering, which suggested an ongoing endochondral ossification- a biological process by which cartilage is replaced with bone.
  • The area where the calcified and uncalcified fibrocartilage met displayed one or more regular tidemarks.
  • The margin isolating the ligament and bone from the fibrocartilage layer exhibited pronounced, irregular interdigitations, or interlocking patterns of tissue.
  • There were differences observed among specimens in terms of fibrocartilage thickness, cellularity (number of cells), and interdigitation size and shape.

Implications

  • The fibrocartilaginous nature of the enthesis in the equine pelvic limb suggests its role in the dissipation of stress, acting as a cushioning system during the movement of the pelvic limb.
  • The findings from the histological examination of the equine enthesis contribute to our understanding of the biomechanics of the horse’s leg. They may also shed light on the pathology of injuries related to the enthesis of the proximal third interosseus muscle and could serve as a significant resource for further research in veterinary medicine and equine care.

Cite This Article

APA
Joostens Z, Audigié F, de la Rebière de Pouyade G, Garigliany MM, Busoni V. (2025). Histological Study of the Normal Proximal Third Interosseus Muscle Enthesis in the Equine Pelvic Limb. Anat Histol Embryol, 54(4), e70059. https://doi.org/10.1111/ahe.70059

Publication

Anatomia, histologia, embryologia
ISSN: 1439-0264
NlmUniqueID: 7704218
Country: Germany
Language: English
Volume: 54
Issue: 4
Pages: e70059

Researcher Affiliations

Joostens, Zoë
  • Department of Medical Imaging, Faculty of Veterinary Medicine, University of Liège, Liège, Belgium.
Audigié, Fabrice
  • Department of Medical Imaging, Cirale-Enva, Goustranville, France.
de la Rebière de Pouyade, Geoffroy
  • Department of Surgery, Faculty of Veterinary Medicine, University of Liège, Liège, Belgium.
Garigliany, Mutien-Marie
  • Laboratory of Veterinary Pathology, Faculty of Veterinary Medicine, University of Liège, Liège, Belgium.
Busoni, Valeria
  • Department of Medical Imaging, Faculty of Veterinary Medicine, University of Liège, Liège, Belgium.

MeSH Terms

  • Animals
  • Horses / anatomy & histology
  • Fibrocartilage / anatomy & histology
  • Muscle, Skeletal / anatomy & histology
  • Hindlimb / anatomy & histology
  • Ligaments / anatomy & histology
  • Male
  • Tendons / anatomy & histology
  • Female

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