Joint complaints are among the most common ailments worldwide, hindering people in performing their everyday activities and diminishing their quality of life. Many publications on pathologic changes and joint dysfunctions, including the temporomandibular joint (TMJ), focus on alterations in bone and cartilage. These publications mostly do not include the consideration of the synovial structural components. However, many pathologic changes as well as the initiation of repair processes of damaged joints occur in this region. This article describes the morphology of the joint cavity (fibrous membrane, synovial membrane) as well as the composition and properties of the synovial fluid (articular synovia) in healthy and diseased human TMJs. Keywords: synovial membrane, synovial fluid, temporomandibular joint, morphology, joint lubrication