The metapodials appear to have been marked during dismemberment from the lower limbs.
Dismemberment is the act of cutting, tearing, pulling, wrenching or otherwise removing, the limbs of a living thing. It may be practiced upon human beings as a form of capital punishment, as a result of a traumatic accident, or in connection with murder, suicide, or cannibalism. As opposed to surgical amputation of the limbs, dismemberment is often fatal to all but the simplest of creatures. In criminology, a distinction is made between offensive and defensive dismemberment