A joint is simply the joining of two or more bones. Normally a joint allows movement of the body to occur. Joints also provide support to the body. Muscles attaching to the bones via tendons provide the force or leverage to move one bone relative to another. Wrapping around the joint itself are ligaments that support and protect the joint. Inside the joints may be found synovial fluids or cartilage, or both, depending upon the type of joint and its function.
Not all joints are meant to provide large ranges of motions. Some joints do not allow any movement at all, but they are still the joining of two bones together. There are three basic kinds of joints:
- Fibrous joints, where the bones are held together by connective tissues. An example of this kind of joint is the joining of the plates of our skull. No movement is desired here so the joints are fibrous, held tightly together.
- Cartilaginous joints, where the bones are held together by cartilage and allow slight movement. Examples of these kinds of joints are the pubic symphysis (where the two ends of the pubic bones are connected by cartilage), between the ribs and their connection to the sternum, and in the spine in the region between adjoining vertebrae. Slight movement is allowed in all these areas but large ranges of movement are not desirable.
- Synovial joints, where there is a space (the synovial cavity) between the bones. This type of joint provides the greatest degree of movement in a variety of ways
Yoga does not try to increase the range of movement in all three kinds of joints; however, for a cartilaginous joint that has grown too tight, Yin Yoga can help to restore the normal range of movement. For the synovial joints, Yin Yoga definitely helps rebuild and even extend the current range of movement, depending upon the type of synovial joint we are targeting.
(Next: Six Kinds of Synovial Joints )