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.[30] 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.