POSTMORTEM LESIONS IN THE INTERCARPAL LIGAMENTS OF THE EQUINE MIDCARPAL JOINT

Objective To determine the frequency of damage to the medial palmar in tercarpal ligament (MPICL), and the range of sizes of the dorsomedial intercarpal ligament (DMICL) of the midcarpal joint in horses with no history of carpal joint disease. Materials and methods Cadaver limbs w ere collected from 72 horses with no history of carpal joint disease. One hundred and forty-two midcarpal joints were dissected and the MPIC L and DMICL were examined. Measurements were made with a digital micro meter. Results MPICL tearing was present in 88 of 96 joints from horse s 2 years and older. Tears were predominantly of the dorsolateral bund le and complete rupture of the dorsolateral and dorsomedial bundles wa s not observed. Tearing was not present in feats less than 4 months of age and the severity of tearing increased significantly with age (P < 0.0001). Severity of tearing was significantly greater in racing Stan dardbreds than racing Thoroughbreds (P < 0.01), but there was no signi ficant difference between racing and non-racing horses. The lateromedi al thickness of the DMICL ranged from 0.4 mm to 2.6 mm in horses 2 yea rs and older. Lateromedial thickness increased significantly with age, and was significantly greater in racing Standardbreds than racing Tho roughbreds (P < 0.01). There was no significant difference between rac ing and nonracing horses.Conclusions Damage confined to the dorsolater al bundle of the MPICL is a common finding in horses over 1 year of ag e and is probably of little clinical significance. Complete rupture of both dorsolateral and dorsomedial bundles is uncommon in horses with no history of midcarpal joint disease. Variation in size of the DMICL is observed in horses of all ages, but is most marked in 2-year-old ho rses.