The lumbrical muscles add for the flexion of your metacarpophalangeal joints and to the extension in the interphalangeal joints. They originate with the flexor digitorum profundus tendons at the palm and insert on the radial element of the extensor tendons with the digits. The ECRB inserts at the base on https://marioqyfk18518.wikilinksnews.com/5237117/crafting_excellence_the_rivet_manual_hand_press_in_artisanal_work