Functional transformation of the fascia brachii lateralis and fascia antebrachii on the forelimb of sports horses
Gyürü, F.
Acta Veterinaria Academiae Scientiarum Hungaricae 29(2): 197-212
1981
ISSN/ISBN: 0001-7205 PMID: 7342748 Document Number: 175927
The antomical structure of the fascia brachii lateralis and fascia antebrachii was examined postmortem in 83 horses (34 sports and 49 work horses). Distal to the deltoid tuberosity and on the lateral surface of fasciae elbow, were thicker than elsewhere on the elbow. Thickening increased with progressing age but was limited to the fascial parts, furnishing attachment of origin to the m. extensor carpi radialis and m. extensor digitorum communis. Thickening apparently develops on a functional basis through a numerical increase in fascial collagen fibers in the critical site. The deltoid tuberosity of humerus furnishes origin to the m. extensor digitorum communis and m. extensor carpi radialis, and the latter has another origin on the proximal end of the humerus. These relations of origin have not yet been described in the literature. In 7-yr-old gallop and jumping horses, the fascia brachii lateralis and fascia antebrachii form distal to the deltoid tuberosity a thick, triangular structure, which subdivides distally into 3 fibrous fascial bands. Two of them converge to the tendon of insertion of the m. extensor carpi radialis and m. extensor digitorum communis and the 3rd band ends on the lateral epicondyle of humerus. Fascial thickening of this kind never takes place in contemporary or older horses used for purposes other than galloping and jumping. The tendinous fascial bands arise by functional thickening of the fascia and serve as a muscle-work-saving fixing apparatus for the carpal and phalangeal joints during extension of the shoulder and elbow joints. The static function of the fascial bands reduces muscular charge by taking over part of strenous muscle work. This can explain the undiminished or even superior stamina of racing horses at a relatively advanced age.