- BS Media
- Published: 26, May, 2017 | Updated: May 26, 2017
- Joint is the point where two or more bones meet. Joints allow different degrees of movement.
- There are many articulations or joints present in the skeleton.
- Joints are classified based upon their structure and the kinds of movements which they permit.
- Three main types of joints are
i. Immovable joints (Synarthroses)
ii. Imperfect movable joints (Amphiarthroses)
iii. Perfect movable joints (Diarthroses)
- With or without joint cavities, permits a small amount of movement. Fibrocartilage is placed between the bones.
- These joints are also called cartilaginous joints or slightly movable joints. Sinovial capsule and ligaments also absent.
- Movable joints are called synovial joints.
- Synovial joint has a synovial or joint cavity, a space between articulating bones.
- Articular cartilage covers the surface of articulating bones.
- Articular cartilage of synovial joint is hyaline cartilage.
- Synovial joints are surrounded by a tubular articular capsule.
- The articular capsule consists of two layers, outer fibrous capsule and inner synovial membrane.
- The synovial membrane secretes synovial fluid which lubricates and provides nourishment to articular cartilage.
- In old age, stiffness of joints is due to the decrease in synovia) fluid.
CLASSIFICATION OF SYNOVIAL JOINTS
iii. Hinge joint is a type of sinovial joint which allows movement in one plane. Elbow joint, knee joint and joints between phallanges of digits are of this type.