Vascular anatomy of the human flexor digitorum profundus tendon insertion

The vascular anatomy of the flexor digitorum profundus (FDP) tendon insertion is described by using a vascular injection and modified Spalteholtz tissue clearing protocol in 36 human cadaver digits. A consistent dense palmar and dorsal vascular supply to the tendon at its insertion into the distal phalanx was observed based on sources from both the distal phalanx and the vinculum brevis profundus. Multiple palmar-dorsal vascular interconnections were seen between these spatially distinct vascular networks, a finding not observed previously in studies of the vascular anatomy of tendon or ligament insertions. Additionally a well-defined dorsal zone of hypovascularity was identified subjacent to the volar plate of the distal interphalangeal joint, within 1 cm of the tendon insertion. Recognition of the vascular supply to the FDP insertion at the distal phalanx permits further evaluation of the vascular, histologic, and cellular events after FDP tendon avulsion and improves the understanding of the biologic response mechanisms involved in bone-tendon healing.