The synovial membrane is a thin layer of tissue that lines the inner surface of the joint capsule, covering all internal joint surfaces except the articular cartilage, and represents an essential structure for normal joint function. Its primary role is the production of synovial fluid, which provides lubrication of the joint surfaces and nourishment of the articular cartilage, as well as regulating the exchange of nutrients and metabolic waste products between the joint cavity and the bloodstream.
The synovial membrane has a rich vascular and nerve supply, making it particularly sensitive to inflammatory processes. Its specialized structure also allows adaptation of the joint volume during different movements.
In pathological conditions such as rheumatoid arthritis, osteoarthritis, or following joint injury, the synovial membrane may become inflamed (synovitis), thickened, or undergo hyperplasia. These changes can lead to increased production of synovial fluid, joint swelling, pain, and reduced function.
Evaluation of the synovial membrane through imaging techniques or, in selected cases, biopsy, plays an important role in the diagnosis and monitoring of inflammatory or autoimmune joint disorders.