Is that a medical term?
Simple term when an unattended object is subject to the rules of gravity.
Simply put the bones and blood vessels in the severed appendage are so badly damaged it may risk infection anyway.
I think that when it was severed the limb was still in free fall. Then probably thrown into the gears and other nasty mechanical things that exist underneath the machine.
But then again I only am Combat Lifesaver qualified all I know is to elevate, tourniqet and reassure.
LOL