Lumbricals are small muscles found in the hand and foot that originate from the tendons of the flexor digitorum profundus. These muscles help to flex the metacarpophalangeal joints and extend the interphalangeal joints. There are four lumbricals in each hand and foot. Some synonyms for lumbricals include the "worm-like muscles", the "worm muscles", or the "little worm tubes". These muscles are important for hand and foot movement and control. Injuries or weakness in the lumbricals can lead to difficulty moving the fingers or toes, making everyday tasks challenging. Keeping these muscles strong with regular exercises can help maintain hand and foot strength.