Estudo morfuncional do mÃsculo ancÃneo atravÃs da observaÃÃo em humanos e eletroneuromiografia de superfÃcie

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

The anconeus, a muscle with peculiar characteristics, is scarcely mentioned in the scientific literature. It is considered by some authors a part of the triceps muscle, while other authors consider it an independent muscle. The anconeus muscle is active during the extension of the elbow, however its effective action on elbow extension is small and the triceps muscle is the main extensor of the elbow. The anconeus muscle may also act as a stabilizer of the elbow joint. There are few studies on the architectural features of the anconeus muscle. Objectives: The aim of this work was (1) to study the morphological and architectural features of the anconeus muscle, (2) to analyze some kinesiological aspects the could help clarify its function and (3) to map its motor end-plat area. Material and method: For the morphologic and architectural studies we dissected twenty adult cadavers fixated with formalin, without distinction of sex, age and ethnic group. To study the action of the anconeus on the elbow joint we modeled the force vector of the muscle by two orthogonal functional components: A tangential component (the only effective in production of rotatory movement) and a radial component (effective on stabilizing the joint). Mapping of the motor end-plate was performed by analyzing the composed muscle action potential recorded over the skin the recover the muscle. Results and conclusions: The anconeus muscle is an independent muscle, presenting origin and insertion distinct form the triceps. Architecturally the anconeus is a penate muscle, with its muscle fibers measuring about one third of the length of the entire muscle. Therefore, the anconeus presents features of a force muscle, instead of an excursion muscle. The anconeus muscle is active during elbow extension, however most of its force is modeled by the radial (stabilizing) component. The tangential component, the only effective on producing movement of rotation, is very small. Therefore, the main function of the anconeus muscle seems to be to stabilize the elbow joint during extension. The motor end-plate area of the anconeus muscle is a line parallel to the ulna. This shape of the motor end-plate area may be predicted by the location of the innervation point in the middle of the muscle fibers and by the architectural features of the anconeus - a penate muscle with fibers that leaves obliquely a tendon expansion and travel towards the ulna, where it attaches

ASSUNTO(S)

motor endplat area arquitetura muscular ancÃneo anconeus cinesiologia, Ãrea de placa motora muscular architecture anatomia patologica e patologia clinica morphology kinesiology morfologia

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