What is the function of the lumbricals during finger movement?

The function of the lumbricals is primarily to assist in metacarpophalangeal (MP) flexion while also allowing for extension at the proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints. This unique action is essential for many intricate finger movements, such as gripping and fine manipulation.

The lumbricals originate from the tendons of the flexor digitorum profundus muscle and insert into the extensor expansion of the fingers. When the lumbricals contract, they pull on the extensor mechanism, which leads to the simultaneous flexion at the MP joints and extension at the PIP and DIP joints. This function is crucial, as it enables the fingers to grasp objects effectively while maintaining the ability to extend the fingers for various tasks.

Understanding the role of the lumbricals in coordinated finger movement emphasizes the complexity of hand dynamics and the interplay between flexor and extensor muscles during activities. Their action is particularly important in activities requiring precision and dexterity, making them vital components of hand function.