Most muscles cross at least one joint and are attached to the articulating bones that form the joint. When such a muscle contracts, it draws one articulating bone toward the other. The attachment to the stationary bone is the origin. The attachment to the movable bone is the insertion. B. Lever Systems and Leverage 1.
Bones serve as levers and joints serve as fulcrums.
C. Arrangement of Fasciculi 1. The muscle fibers are arranged in a parallel fashion within each bundle, but the arrangement of the fasciculi with respect to the tendons may take one of four characteristic patterns. Fascicular arrangement is correlated with the power of a muscle and the range of motion. D. Group Actions 1. Most movements also involve muscles called synergists, which serve to steady a movement, thus preventing unwanted movements and helping the prime mover function more efficiently.