(Articulationes Digitorum Manus; Interphalangeal Joints)
The interphalangeal articulations are hinge-joints; each has a volar and two collateral ligaments. The arrangement of these ligaments is similar to those in the metacarpophalangeal articulations. The Extensor tendons supply the place of posterior ligaments.
The thumb has only 1 interphalangeal joint, all other digits have a proximal and a distal interphalangeal joint.
The only movements permitted in the interphalangeal joints are flexion and extension; these movements are more extensive between the first and second phalanges than between the second and third. The amount of flexion is very considerable, but extension is limited by the volar and collateral ligaments.