The lumbrical muscles add to the flexion in the metacarpophalangeal joints and also to the extension of your interphalangeal joints. They originate from your flexor digitorum profundus tendons for the palm and insert on the radial aspect of the extensor tendons with the digits. wikiHow is where by trustworthy research https://marioqyfk18518.wikilinksnews.com/5237117/crafting_excellence_the_rivet_manual_hand_press_in_artisanal_work