Interphalangeal articulations of hand

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Associate Editor-In-Chief: Cafer Zorkun, M.D., Ph.D. [2]

Overview

The interphalangeal articulations of hand are hinge-joints of the phalanges of the hand. There are two sets (except in the thumb):

"proximal interphalangeal joints" (PIP), those between the first (also called proximal) and second (intermediate) phalanges
"distal interphalangeal joints" (DIP), those between the second and third (distal) phalanges

Each joint has a volar ligament and two collateral ligaments.

The arrangement of these ligaments is similar to those in the metacarpophalangeal joints (also known as MCP joints).

The extensor tendons supply the place of posterior ligaments.

The only movements permitted in the interphalangeal joints are flexion and extension.

Flexion is more extensive, about 100°, in the PIP joints and slightly more restricted, about 80°, in the DIP joints.
Extension is limited by the volar and collateral ligaments.

The muscles generating these movements are:

Location	Flexion	Extension
fingers	the flexor digitorum profundus acting on the proximal and distal joints, and the flexor digitorum sublimis acting on the proximal joints	mainly by the lumbricales and interossei, the long extensors having little or no action upon these joints
thumb	the flexor pollicis longus	the extensor pollicis longus