The accessory ligament of the deep digital flexor tendon (DDFT)—the inferior check ligament (ICL)—is a strong, fibrous band that is the direct continuation of the common palmar ligament of the carpus. Desmitis of the ICL can occur alone or develop secondarily to injury to the superficial digital flexor tendon (SDFT). In horses with severe ICL damage, the DDFT might also be affected.
Injury of the ICL is relatively uncommon in racehorses but is common in ponies and warmblood breeds. ICL injury is usually unilateral.
Diagnosis of ICL injury is based on clinical signs, which include swelling in the proximal one-third of the metacarpus dorsal to the DDFT. Ultrasonographic examination is typically confirmatory, showing areas of enlargement, fiber pattern disruption, and loss of the normal border of the ligament.
Injury to the ICL is usually treated with rest and controlled exercise, sometimes along with shock wave therapy and/or intralesional injection of platelet-rich plasma or stem cells. Desmotomy of the ICL has also been performed in horses that did not respond to conservative therapy.
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Also see pet owner content regarding disorders of the carpus and metacarpus in horses.
