Equis ISSN 2398-2977

PIP joint: diseases - overview

Synonym(s): Proximal interphalangeal joint disease, pastern joint disease

Contributor(s): Helen Herinckx, Graham Munroe


  • Incidence: the proximal interphalangeal joint is less commonly associated with lameness than more mobile joints such as the carpus or fetlock, or the foot.
  • Cause: acute or chronic trauma   →   conditions such as osteoarthritis, luxation or fracture.
  • Signs: varies from mild lameness to non-weightbearing. Peri-articular ringbone may be asymptomatic.
  • Diagnosis: clinical examination, radiography   Forelimb: radiography    Hindlimb: radiography  and intra-articular anesthesia   Forelimb: joint anesthesia    Hindlimb: joint anesthesia  are often sufficient.
  • Treatment: depends on cause.
  • Prognosis: depends on cause.






Congenital and perinatal conditions

Predisposing factors



  • The proximal interphalangeal (PIP) joint is the articulation between the distal aspect of the proximal phalanx and the proximal aspect of the middle phalanx. 
  • Collateral ligaments, abaxial and axial ligaments provide stability to the joint.
  • Several ligaments and tendons course over the pastern region, including the superficial digital flexor tendon (SDFT) and deep digital flexor tendon (DDFT).
  • Proximity to the ground, paucity of soft tissue cover dorsally and laterally, the degree of flexion occurring at this site and important soft tissue structures (SDFT, DDFT) on its palmar/plantar surface all contribute to this region being vulnerable to injury.
  • Depends on the individual joint disease.
  • See also Joint: synovial pathobiology   Joint: synovial pathobiology  .


  • Acute onset for fractures, luxations and traumatic lesions.
  • Chronic and insidious onset for osteoarthritis, bone cysts, DJD.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Garvican E & Clegg P (2007) Clinical aspects of the equine proximal interphalangeal (pastern) joint. UK Vet 12 (6), 11-16 VetMedResource.

Other sources of information

  • Ruggles A J (2003) The Proximal and Middle Phalanges and Proximal Interphalangeal Joint. In: Diagnosis & Management of Lameness in the Horse. Eds: Ross M W & Dyson S J. Saunders, USA. pp 342-348.