Human poly-articular muscles: An anatomical comment

Bi-articular muscles form a subclass of poly-articular muscles. Muscles in human limbs belonging to these classes are enumerated. For some of these muscles experimental evidence had been given that they direct forces on the environment and move segments of the limbs in a unique way. They perform the combination of these effects in cooperation with mono-articular antagonists. Such muscles are situated in the lower limb. Analyses of upper limb movements were less convincing. They were not complete. In the literature the kinematic studies were found from which a hypothesis about the functioning of the poly-articular muscles moving the fingers may be deduced. Expansion of an experiment of Long et al. (1970) with analysis of forces exerted may provide an interpretation of the cooperation of finger poly-articular muscles. The terms antagonist and synergist are redefined.