The articular capsule is a fibrous structure that surrounds a synovial joint, providing stability and support. It consists of two layers: the outer fibrous layer, which is made of dense connective tissue, and the inner synovial membrane, which produces synovial fluid. This fluid lubricates the joint, reducing friction during movement. The articular capsule plays a crucial role in maintaining joint integrity and allowing for a range of motion. It connects the bones at the joint and helps protect the cartilage and other internal structures from injury. Proper functioning of the articular capsule is essential for joint health and mobility.