Joints

A synovial joint is characterised by the presence of a fluid-filled joint cavity contained within a fibrous capsule.

It is the most common type of joint found in the human body, and contains several structures which are not seen in fibrous or cartilaginous joints.

The three main features of a synovial joint are: (i) articular capsule, (ii) articular cartilage, (iii) synovial fluid.

The articular capsule surrounds the joint and is continuous with the periosteum of articulating bones.

It consists of two layers:

• Fibrous layer (outer) – consists of white fibrous tissue, known the capsular ligament. It holds together the articulating bones and supports the underlying synovium.

• Synovial layer (inner) – a highly vascularised layer of serous connective tissue. It absorbs and secretes synovial fluid, and is responsible for the mediation of nutrient exchange between blood and joint. Also known as the synovium.