Middle Phalanx Anatomy

  • This bone is found between the proximal and distal phalanges in the fingers (except for the thumb which does not have a middle phalanx)
  • The middle phalanges are small long bones of the fingers.
  • The base of the middle phalanx, which is part of the PIP joint, and the distal head, which is part of the DIP joint, are covered with articular cartilage.
  • The middle phalanx has five basic parts: The head or distal epiphysis, the neck or metaphysis, the shaft or diaphysis, the proximal metaphysis, and the base or proximal epiphysis.
  • The concave proximal ends of the middle phalanx articulate with the proximal phalanx.
  • The distal end of the 2nd, 3rd, 4th, and 5th middle phalanges articulate with the base of the 2nd, 3rd, 4th, and 5th distal phalanges.
  • Dorsally the central slip, which part of the extensor hood, inserts into a dorsal tubercle at the base of the middle phalanx.
  • Palmarly the FDS tendon inserts into the palmar aspect of the base of the middle phalanx.
Diagrams & Photos
  • Normal X-ray Image of distal phalanx, middle phalanx, proximal phalanx, and metacarpals.
    Normal X-ray Image of distal phalanx, middle phalanx, proximal phalanx, and metacarpals.
  • Anatomic Image of distal phalanx, middle phalanx, proximal phalanx, and metacarpals.
    Anatomic Image of distal phalanx, middle phalanx, proximal phalanx, and metacarpals.
Key Points
  1. The fossae on the radial and ulnar sides of the middle phalanx head are the origin site of the DIP joint collateral ligaments.
  2. The head of the middle phalanx has two condyles with a small shallow intercondylar groove.
  3. In the growing child there is an epiphyseal plate in the base of the middle phalanx.
Anatomy References
Anatomic Abbreviations
Hand Surgery Resource Anatomy Diagnostic Guide (Chapter)