Читать книгу Arthritis For Dummies - Barry Fox - Страница 15

To accommodate the bends, twists, and turns that we all perform without even thinking, the skeletal system is made up of different shapes and sizes of bones, which connect to form different kinds of joints. The joints are categorized according to how much motion they allow:

 Synarthrodial joints allow no movement at all. You can find these in the skull, where the bones meet to form tough, fibrous joints called sutures. Because they don’t move, arthritis doesn’t affect them.

 Amphiarthrodial joints, such as those in the spine or the pelvis, allow limited movement. Generally, these joints aren’t attacked by arthritic conditions as often as others. (A slipped disc is not arthritis.)

 Synovial joints allow a wide range of movement; most of our joints fall into this class. Synovial joints come in all kinds of interesting variations including those that glide, hinge, pivot, look like saddles, or have a ball-and-socket type structure. (For more on these joints, take a look at the section “Looking at the types of synovial joints” later in this chapter.) Because of the synovial joints, you can bend over and pick a flower, kick up your heels while swing dancing, reach for a glass on a high shelf, and turn around to see what’s going on behind you. Unfortunately, these joints are also the ones most likely to be hit with arthritis, precisely because they do move!