What components constitute the suspensory apparatus of the horse, and what is its role in the stay mechanism?

What components constitute the suspensory apparatus of the horse, and what is its role in the stay mechanism?

• A. Interosseous (suspensory) ligament, proximal and distal sesamoidean ligaments, and the proximal sesamoid bones
• B. Patellar ligament and extensor tendons
• C. Lacertus fibrosus
• D. Carpal ligaments

Answer: (A)

The stay mechanism relies on a ligamentous sling that supports the fetlock, known as the suspensory apparatus. Its components are the interosseous (suspensory) ligament along the back of the cannon bone, the proximal and distal sesamoidean ligaments that connect the sesamoid bones to the phalanges, and the proximal sesamoid bones themselves, which act as pulleys for these ligaments. When the limb bears weight, this system tightens and spreads the load across the fetlock, preventing hyperextension and effectively allowing the horse to stand for long periods with little muscular effort. When the weight is removed, tension drops and some flexion becomes possible. The other structures listed are not part of the suspensory apparatus and serve different roles in other parts of the limb.

The stay mechanism relies on a ligamentous sling that supports the fetlock, known as the suspensory apparatus. Its components are the interosseous (suspensory) ligament along the back of the cannon bone, the proximal and distal sesamoidean ligaments that connect the sesamoid bones to the phalanges, and the proximal sesamoid bones themselves, which act as pulleys for these ligaments. When the limb bears weight, this system tightens and spreads the load across the fetlock, preventing hyperextension and effectively allowing the horse to stand for long periods with little muscular effort. When the weight is removed, tension drops and some flexion becomes possible. The other structures listed are not part of the suspensory apparatus and serve different roles in other parts of the limb.