Show hunters’ and jumpers’ forelimbs withstand tremendous impact, so the bones of their knees and neighboring ligaments at the upper part of the cannon bone are prone to injury. It’s important that veterinarians be able to detect and diagnose such insults early, which requires skill and practice, noted one sport horse practitioner at the recent American Association of Equine Practitioners Convention.

At the 2013 meeting, held Dec. 7-11 in Nashville, Tenn., Kit Miller, DVM, Fédération Equestre Internationale-accredited veterinarian and founder of Miller and Associates, in Brewster, N.Y., described how ambulatory veterinarians can identify these lesions using routine imaging modalities.

Miller urged practitioners to use diagnostic anesthesia in order to rule out problems in the distal (lower) limb. Following sequential anesthesia, working from the bottom of the limb upward, if the veterinarian does not localize the horse’s lameness to the lower limb Miller suggested using a lateral palmar nerve block to isolate the source of lameness to the carpal (knee) area.

He listed some characteristics of injuries within the carpal sheath (which surrounds the superficial and deep digital flexor tendons in the back of the knee, extending several inches above and below the knee joint) and the proximal (upper) cannon bone area:

  • Bony lesions might impinge upon the carpal sheath and irritate the deep digital flexor tendon;

  • Not all lesions are centrally located, so imaging should also include medial and lateral (both sides) views, not just the midline, which focuses primarily on the center of the limb