Which part of P3 is affected by toe ulcers?

• A. Flexor tuberosity
• B. Proximal articular surface
• C. Apex
• D. Dorsal border

Answer: (C)

Toe ulcers typically affect the apex of P3—the most distal point of the coffin bone on the solar surface. This area bears direct, concentrated load with each step, and the overlying hoof horn there is relatively thin, making the corium vulnerable to trauma and pressure necrosis. Repeated loading or abnormal weight distribution can ulcerate the solar surface at the apex and may extend into the bone. The other regions described are not the primary sites for toe ulcers: the flexor tuberosity is a ventral projection for tendon attachment, the proximal articular surface forms the joint with P2, and the dorsal border is the edge under the hoof wall—none are the typical ground-contact zone where toe ulcers arise.