Capsular Ligament Injuries of the Finger Joints

Abstract

All the interphalangeal joints are of the ginglymoid type. From the center of rotation of the phalangeal heads, the collateral ligaments extend distally to the base of the next bone on each side. Palmarward they become the accessory collateral ligaments, which are not inserted into the bone but radiate to the volar fibrocartilage plate. This plate is broadly fixed at the base of the distal bone, separating the flexor tendon sheath from the articular space, and centralward becomes the thin flaccid pars. The latter is taut during maximum extension and folded in moderate flexion. During maximum flexion it is stretched in a central direction by the rigid fibrocartilage plate. Below the flaccid pars is the volar capsule sac.