Objectives: To describe the radiographic appearance of the dorsoproximal aspect of the sagittal ridge of the third metacarpal/metatarsal bone in Warmblood horses.
Methods: The lateromedial radiographic projections of the metacarpo-/metatarsophalangeal joints performed on horses as a part of stallion selection were used. The dorsal aspect of the distal third metacarpal/metatarsal bone was divided in two areas. The appearance of the bone surface in area I was classified as normal, irregular, notch, indentation and lucency. For area II, the categories were normal, irregular, depression or lucency and flattening of the sagittal ridge. Other abnormalities at the dorsal aspect were also noted.
Results: In area I, 51.5% of the ridges appeared normal, 19.3% were irregular, 8.9% had a notch, 8.1% had a lucency, and 12.2% had an indentation. In 1.2% of the horses a fragment was present, and in 1.7% a fragment was suspected. In area II, 90.6% of the metacarpo-/metatarsophalangeal joints were normal, 6.2% were irregular, 2.9% showed a depression or lucency, and the sagittal ridge in 0.2% was flattened. A fragment was present in 0.3%, and suspected in 0.4%.
Clinical significance: Morphological variation is present at the dorsal aspect of the metacarpo-/metatarsophalangeal joint in young Warmblood stallions. These various aspects should be recognised and described in horses presented for prepurchase examination. However, their clinical relevance in the individual horse is unclear and needs further investigation.