The elbow joint is a hinge joint that connects the humerus in the upper arm to the radius and ulna in the forearm. It allows for flexion and extension, enabling the arm to bend and straighten. The joint is stabilized by ligaments and surrounded by a capsule filled with synovial fluid, which reduces friction during movement. In addition to its primary function, the elbow joint also allows for limited rotation of the forearm, which is essential for actions like turning a doorknob. Proper functioning of the elbow joint is crucial for daily activities such as lifting, throwing, and pushing.