noun, plural: synovial joints
Synovial joints are movable joints that enable abduction, adduction, extension, flexion, and rotation. It is comprised of a sac-like fibrous joint capsule, a synovial cavity filled with a synovial fluid, and a layer of articular cartilage. The joint capsule is the capsule enveloping a synovial joint. In general, it is comprised of two layers. The first layer is a fibrous membrane that lies in the outer part of the capsule. It is made up mainly of ligaments, owing to its fibrous nature. The second layer, which is also the inner layer of the joint capsule, is the synovial membrane.
The synovial membrane is the inner layer of the joint capsule made up of intima and subintima (an outer layer of connective tissue). The intima is the inner layer of the synovial membrane consisting of two types of cells: fibroblast-like (type B) synovial cells and macrophage-like (type A) synovial cells. The type B synovial cells release components of the synovial fluid into the synovial cavity. The synovial membrane, therefore, is involved in secreting components for the synovial fluid that fills the synovial cavity. The synovial fluid is the clear, viscid fluid that functions by lubricating the articulating joints, supplying nutrients and oxygen, and removing metabolic wastes.
- stratum synoviale