Suspensory desmitis is a common problem and affects a broad cross section of equine athletes in various disciplines. For this study, the proximal portion of the suspensory ligament was collected from 6 horses without suspensory ligament injury (16 ligaments) and 4 horses with degeneration of the suspensory ligament (11 ligaments). Specimens were collected immediately after euthanasia and placed in neutral-buffered 10% formalin. The tissue was fixed, sectioned, and stained with hematoxylin and eosin (H&E),

Masson's trichrome, and for apoptosis by the terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) technique. Histological changes in the abnormal ligaments included mineralization, fibroplasias, neovascularization, collagen degeneration, and significant architecture disruption in 2 ligaments. There was a trend for increased apoptosis in the injured ligaments compared to the normal ligaments.