The preferred placement of the obstetrical chain is with the loop below (distal to) the dew claws and the large link on the dorsal aspect of the foot. When the chain is relaxed it sometimes falls off. Therefore some users prefer to place the chain above the pastern joint. When only placed above or proximal to the pastern, too much force is placed on the metacarpal or metatarsal bone, which can lead to fractures. A compromised application is shown in this illustration, where the actual force of the pull is placed on the distal portion of the foot.
Drost M (1978)