Where is the ultrasound probe placed to evaluate the proximal suspensory ligament in the hind limb?

Where is the ultrasound probe placed to evaluate the proximal suspensory ligament in the hind limb?

• A. Along the lateral cannon bone at the proximal suspensory region.
• B. On the dorsal aspect of the fetlock joint.
• C. On the palmar aspect of the distal phalanx.
• D. On the medial carpus.

Answer: (A)

The proximal suspensory ligament runs along the cannon bone near the fetlock, so the best window to evaluate it is along the lateral aspect of the cannon bone in the proximal suspensory region. Placing a high-frequency linear transducer there lets you follow the ligament fibers from the cannon bone toward the proximal sesamoid area, assessing fiber continuity, thickening, or any tearing. You can image in the long axis to appreciate fiber pattern and in cross-section to measure cross-sectional area.

Other windows don’t visualize the PSL well: the dorsal fetlock area focuses on extensor tendons and joint structures, the palmar aspect of the distal phalanx relates to the navicular region and related structures, and the medial carpus targets carpal ligaments and tendons rather than the proximal portion of the suspensory ligament.