Ligaments (ligamenta) are that part of the joint which lends it strength; they direct and check the action of the joints. Therefore, guiding and check ligaments can be distinguished. Since the number of ligaments in the human body is very great, to study and remember them, one must know the general laws of their arrangement. Ligaments guide the movement of the articular surfaces on a defi­nite pivotal axis of a givon joint and are consequently distributed in each joint according to the number and position of its axes. Ligaments are arranged: (a) perpendicular to the given pivotal axis and (b) mainly at the ends of the axis. 3. They are located in the plane of the given movement in the joint. In an interphalangeal joint with a single frontal rotation axis, for instance, the guiding ligaments stretch along the sides of the axis (ligamenta collateralia) and vertically. In the biaxial elbow joint, the collateral liga­ments also run vertically, perpendicular to the frontal axis, at its ends, while the annular ligament (lig. anulare) stretches horizontally, perpendicular to the vertical axis. Finally, ligaments in the multiaxial hip joint are arranged in different directions.