The chain saw as its name implies, is a chain composed of numerous links or sections, each with a serrated edge, each united with strong rivets and having a handle attached to each extremity.  One of the handles is removable so that it can be passed underneath the bone, either with a large threaded needle or by means of a chain saw carrier.  In either case the carrier provides for passage of a ligature beneath the bone by which the chain saw is drawn into position