Most of fixed joints of the body are synovial. In such kinds of joints, ends of the bones are covered by a cartilage (articular hyaline cartilage) which makes a thin and smooth joint. In it, there is a joint cavity in which there is a clean, thick, sticky and oily fluid named synovial fluid which keeps the joint lubricated and provides nutrition to the articular cartilage without blood vessel. The joint is surrounded by a fibrous articular capsule in which there is a lining of synovial membrane. This lining is not present on the ends, cartilage or disc of bone. The fibrous capsule is attached with thick layer of cologne fibers which are called ligament. There are much free movements in such kind of joints comparison to other joints.
Synovial joints can be divided into several groups according to the limitation of movements and sizes of articulating surfaces of bones-
Such kinds of joints are called turning points too. They can move only in one direction. Only flexion and extension are only possible in such kinds of joints. Elbows, knees, ankles, jaws and fingers have such kinds of joints.