Distal Interphalangeal (DIP) Joints Definition

The distal interphalangeal (DIP) joints are the joints closest to the tips of the toes, fingers, and thumbs.

In medical terminology, DIP joints are synovial joints located where middle and distal phalanges meet. Phalanges are the small bones in the fingers, thumbs, and toes.

The DIP joints are hinge joints, meaning that they bend and straighten along one plane with little to no side-to-side movement.

Arthritis in DIP joints

DIP joints can be affected by arthritis, particularly osteoarthritis and psoriatic arthritis. Pain and swelling in the DIP joints is sometimes the first symptom of psoriatic arthritis.

DIP joints are less likely to be affected by rheumatoid arthritis. When DIP joints are affected by RA, it is typically only after symptoms appear in the middle knuckles (proximal interphalangeal joints) or knuckles at the base of the finger (metacarpophalangeal joints).

An arthritic DIP joint may:

  • Feel painful and/or stiff
  • Be tender
  • Look swollen
  • Have less range of motion

Arthritic damage to a DIP joint may be diagnosed by a physician. Diagnosis may be confirmed with an x-ray or other medical imaging. Treatment recommendations will depend on the type of arthritis, and may include but not be limited to medications, occupational therapy, splinting, or therapeutic injections. Surgery is rarely recommended.