The deep digital flexor tendon (DDFT) uses which bone as a fulcrum point?

• A. cannon bone
• B. proximal phalanx
• C. navicular
• D. pastern bone

Answer: (C)

The key idea is that tendons use fixed points on bones as pulleys to change the direction and leverage of their pull. The deep digital flexor tendon travels down the limb and passes over the navicular bone, which serves as a pulley-like fulcrum. This arrangement redirects the tendon’s force to bend and flex the coffin joint, allowing the horse to extend and retract the toe efficiently. The other bones mentioned aren’t the pulley point for this tendon in this region, so the navicular bone is the correct fulcrum.