Amphiarthroses

These joints, as the name indicates, share some characters with both of the preceding groups. In them the segments are directly united by a plate of fibro-cartilage, and usually by ligaments also. The amount and kind of movement are determined by the shape of the joint surfaces and the amount and pliability of the uniting medium. These joints are all medial in position, and are best illustrated by the joints between the bodies of the vertebræ. There is usually no joint cavity, but in certain situations a rudimentary one exists.