The metacarpophalangeal joints, commonly known as MCP joints, are the connections between the metacarpal bones of the hand and the phalanges of the fingers. These joints allow for a wide range of motion, including flexion, extension, abduction, and adduction, enabling the fingers to grasp and manipulate objects effectively. Each MCP joint is a synovial joint, which means it is surrounded by a capsule filled with synovial fluid that lubricates the joint. The structure of the MCP joints includes ligaments that provide stability and cartilage that cushions the bones, ensuring smooth movement during hand activities.