'The Severed Arm' (1973) – Tom Alderman.

This luridly lop-sided, limb-lopping blood spiller finds a grungy group of amateur cave explorers trapped in a collapsed mine, and on the 7^th diabolical day of despair a barbarous decision is grimly taken which sinisterly seals the men's fates no less severely than the seemingly impregnable rocks weighing so heavily above them! This deliciously grimy-looking 70s grindhouse slasher is a grisly, far from armless B-Horror about the asinine antics of an amped-up amputee's vengefully hands-on socket-popping killing spree that forces the fear-clenched viewer to disable their disbelief, crudely cut all thighs to known reality in order to better experience the cartilage crippling calamity herein! As this deranged appendage acquiring vendetta reaches its hellaciously hatchet-hacking, sinew slashing conclusion that will will severely sever any last vestiges of cinematic credulity!!! 'The Severed Arm' recklessly reaches the bloodier parts many other less dextrous horrors dare not reach!!!' You've certainly got to hand it to Director Tom Alderman as his gruesomely gripping shocker puts you directly into Arms way!!!!