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Effects of Thoracic Posture on the Nuchal Ligament in Foetal Foals
Author(s) -
Nestadt C,
Davies H
Publication year - 2014
Publication title -
equine veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 87
eISSN - 2042-3306
pISSN - 0425-1644
DOI - 10.1111/evj.12267_135
Subject(s) - thorax (insect anatomy) , anatomy , medicine , ligament , lamella (surface anatomy)
Controversy surrounds certain head and neck postures in sport horses and their potential impact on the nuchal ligament. Methods Three dead near‐term equine foetuses in lateral recumbency with upper‐side neck musculature removed to expose the nuchal ligament were placed in 6 head and neck positions ( HNP 's) between extreme hyperflexion and hyperextension, along with 3 thoracic positions: Low, Medium and High. In each of these 18 positions, the funicular length, lamella dorsoventral width at the level of C4, and craniocaudal length of the 5 major lamella bands of the nuchal ligament were measured manually. Results In intermediate HNP 's ( HNP 1, HNP 2), thoracic postures significantly impacted nuchal ligament measurements. Compared to the Medium thorax position, depression and elevation of the thorax decreased lamella sheet widths by 24% (P = 0.014) and 11% (P = 0.267) respectively for HNP 1, and by 8% (P = 0.01 for both depression and elevation) for HNP 2. More extreme head and neck positions were not associated with any change in measurements of the nuchal ligament with changes in thoracic position. Conclusions A decreased width suggests increased tension in an elastic structure. Hence, if the anatomical connections are similar in adults, extreme head and neck postures may reduce the effect that thoracic posture might have on the nuchal ligament in certain unnatural positions required in sport horses and may interfere with normal elastic energy storage in the nuchal ligament during movement. Ethical Animal Research The study was performed on material collected during post‐mortem examination. Explicit owner informed consent for participation in this study is not stated. Sources of funding: none. Competing interests: none.