What is proximal suspensory desmitis (PSD) and which limb is most often affected?

• A. Inflammation of the proximal suspensory ligament, most commonly affecting the front limb.
• B. Inflammation of the distal suspensory ligament, most commonly affecting the front limb.
• C. Inflammation of the proximal suspensory ligament, most commonly affecting the hind limb.
• D. Inflammation of the proximal suspensory ligament, affecting both equally.

Answer: (C)

Proximal suspensory desmitis is inflammation or injury of the proximal part of the suspensory ligament that runs along the back of the cannon bone and supports the fetlock. This region bears significant stress from loading and propulsion, so repetitive strain can lead to pain, swelling, and lameness centered near the base of the limb.

It is most commonly seen in the hind limb, likely because the hind limb bears more load during propulsion and experiences greater stress at the proximal suspensory area. While it can occur in front limbs, the hind limb is the typical site.

In short, the description matches inflammation of the proximal suspensory ligament, with the hind limb being the limb most often affected.