Name the distal sesamoidean ligaments and their role in the stay apparatus.

Name the distal sesamoidean ligaments and their role in the stay apparatus.

• A. Straight, oblique, and cruciate distal sesamoidean ligaments connect the proximal sesamoid bones to the distal phalanx, stabilizing the fetlock during weight-bearing
• B. Lateral and medial collateral ligaments stabilize fetlock
• C. Interosseous ligament suspends fetlock
• D. Extensor tendons stabilize fetlock

Answer: (A)

The distal sesamoidean ligaments—straight, oblique, and cruciate—stretch from the distal surfaces of the proximal sesamoid bones to the dorsal part of the distal phalanx. They provide passive support to the fetlock when the limb bears weight by tying the sesamoids to the coffin bone and resisting hyperextension, helping the joint stay aligned under load. In the stay apparatus, these ligaments work with the suspensory apparatus and the flexor system to keep the fetlock extended during stance, allowing the horse to stand with less muscular effort. While other structures stabilize or move the joint in different ways—collateral ligaments stabilize the joint, the interosseous ligament suspends the fetlock, and extensor tendons mainly extend the joint—they are not the distal sesamoidean ligaments responsible for this specific passive stabilization.