STABILITY OF SYNOVIAL JOINTS
Synovial joints allow a wide range of motion and have to be protected from movements beyond the normal range that can damage the joint. They are protected by:
1. the collagen fibers of the capsule
2. intracapsular and extracapsular ligaments
3. the tendons that surround the joint
4. the shape of the articular surface and the bones
5. muscles and other structures that surround the joint.
The structures that stabilize the joint may vary. For example, the hip joint is extensively supported by in-tracapsular as well as extracapsular ligaments. The articular surface of the femur is rounded, providing further stability. The thick muscles around the hip make it strong and stable. The elbow, however, is sta-bilized more by the bones that tend to interlock with each other as the elbow moves.