The main idea is protecting the injured extensor tendon at the fingertip during the initial healing period. In Phase I, the goal is to immobilize the distal interphalangeal joint in a slight flexion to prevent extension and stress on the healing tendon, while still allowing gentle motion at the rest of the finger to maintain glide and prevent stiffness. A dorsal blocking orthosis does exactly this: it sits on the back of the finger and blocks extension at the DIP, keeping it in flexion so the tendon can heal, while permitting controlled flexion and movement at the other joints. Using a volar splint with wrist extension doesn’t specifically protect the DIP extensor mechanism, immobilizing the wrist instead; no immobilization or forcing immediate active finger flexion would risk re-injury or poor healing. Hence, the dorsal blocking orthosis is the appropriate choice for Phase I immobilization.