The volar plates are fibrocartilaginous structures on the palmar aspect of each finger joint (MCP, PIP, and DIP) that prevent hyperextension and form the floor of the flexor tendon sheath. The PIP joint volar plate is clinically most important — its avulsion from the base of the middle phalanx in dorsal PIP dislocations produces the characteristic dorsal lip avulsion fragment on radiograph and leads to PIP joint swan neck deformity if the avulsion is extensive. The check-rein ligaments at the volar plate margins prevent excessive proximal plate retraction.
| Origin | Palmar surface of the proximal bone at each finger joint (MCP, PIP, DIP) |
|---|---|
| Insertion | Palmar surface of the base of the distal bone at each joint |
| Actions | Primary restraint against hyperextension; forms the floor of the flexor tendon sheath; contributes to joint stability against dorsal dislocation |
|---|
Volar plate avulsion at the PIP joint from a dorsal dislocation produces a radiographic avulsion fragment at the base of the middle phalanx that must be assessed for size — small avulsions (less than 40 percent of the articular surface) are stable and treated with extension block splinting, while larger avulsions risk volar instability requiring surgical fixation. Chronic volar plate laxity allows the PIP joint to hyperextend into the swan neck posture.
PIP joint volar plate tear from dorsal dislocation producing a characteristic avulsion fracture at the middle phalanx base, managed with extension block splinting for stable injuries and surgical fixation for large fragments.
