Which part of the muscle is immobile and attached to the skeleton?

The origin of a muscle is the part that is immobile and attached to a fixed structure, such as a bone in the skeleton. This connection allows the muscle to exert force and produce movement at the insertion point, which is typically located on the bone that moves when the muscle contracts. The origin serves as a stable anchor from which the muscle can generate power. Understanding this feature helps in comprehending how muscles function in relation to each other and to the skeletal system during various movements. The other parts, such as the insertion and belly, have different roles in muscle function. The insertion connects to the moving bone during contraction, while the belly is the central, fleshy part of the muscle.