Long Proximal Phalanx Anatomy

  • The proximal phalanges are small long bones of the fingers.
  • The base of the proximal phalanx, which is part of the MP joint, and the distal head, which is part of the PIP joint, are covered with articular cartilage.
  • The proximal 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 proximal phalanx articulate with the metacarpals.
  • The distal end of the 2nd, 3rd, 4th, and 5th proximal phalanges articulate with the base of the 2nd, 3rd, 4th, and 5th middle phalanges.
  • Note the proximal phalanx of the finger distal two thirds is located in the finger sections (2-5) and the proximal one third is located in section 7.
Diagrams & Photos
  • Bones of the fingers and hand.
    Bones of the fingers and hand
  • Dorsal anatomic view of the finger bones.
    Dorsal anatomic view of the finger bones.
Key Points
  • The fossae on the radial and ulnar sides of the proximal phalanx head are the origin site of the PIP joint collateral ligaments.
  • The head of the proximal phalanx has two condyles with a shallow intercondylar groove.
  • The shaft of the proximal phalanx is slightly convex dorsally and concave volarly.
  • In the growing child there is an epiphyseal plate in the base of the proximal phalanx.
  • The only muscles that insert into the proximal phalanx are the 2nd, 3rd, and 4th interossei muscles.
  • The proximal phalanges of the fingers are displaced during MP joint dislocations and complex dislocations and remain in their anatomic position during PIP dislocations.
  • Simple stable non-displaced fractures of the phalanges can be treated with splinting while fractures that are unstable due to displacement or comminution may require percutaneous pining or open reduction and internal fixation.
Anatomy References
Anatomic Abbreviations
Hand Surgery Resource Anatomy Diagnostic Guide (Chapter)