A joint or articulation (or articular surface) is the connection made between bones, ossicles, or other hard structures in the body which link an animal's skeletal system into a functional whole. [1][2][3] They are constructed to allow for different degrees and types of movement.
Joint, in humans and other animals, structure connecting two or more adjacent parts of the skeleton. Not all joints move, but, among those that do, motions include spinning, swinging, gliding, rolling, and approximation. Learn about the different types of joints and their structure and function.
A tissue called the synovial membrane lines the joint and seals it into a joint capsule. The synovial membrane secretes a clear, sticky fluid (synovial fluid) around the joint to lubricate it.
In a joint, the ends of the bones are covered with cartilage. Cartilage is a smooth, tough, resilient, and protective tissue composed of collagen, water, and proteoglycans to reduce friction as joints move.