Where muscle begins and is located nearest the mid-line of the body or on a less movable part of the skeleton?

The muscle that begins nearest the mid-line of the body and is located on a less movable part of the skeleton is referred to as the "origin" of the muscle. The origin typically attaches to a stable bone or structure, allowing the muscle to exert force effectively during movement. In contrast, the "insertion" of the muscle is usually found on the more movable part of the skeleton, allowing for greater mobility and movement.