In the<unk>  (ginglymus), the articular surfaces are moulded to each other in such a manner as to permit motion only in one plane, forward and backward, the extent of motion at the same time being considerable.
The direction which the distal bone takes in this motion is seldom in the same plane as that of the axis of the proximal bone; there is usually a certain amount of deviation from the straight line during flexion.
The articular surfaces are connected together by weak collateral ligaments, which form their chief bond of union.
The best examples of ginglymus are the interphalangeal joints and the joint between the humerus and ulna; the knee- and ankle-joints are less typical, as they allow a slight degree of rotation or of side-to-side movement in certain positions of the limb.
Hinge joint
Jaw
Alar plate
Rayon
Fibrous joint
Club foot
Head of radius
Metatarsus