411 © Schattauer 2010 Vet Comp Orthop Traumatol 6/2010 Original Research Radiographic features of the dorsal condylar sagittal ridge of the third metacarpal and metatarsal bones in young Warmblood stallions S. Hauspie 1 ; A. Martens 2 ; J. Declercq 2 ; V. Busoni 3 ; K. Vanderperren 1 ; H. van Bree 1 ; J. H. Saunders 1 1 Department of Veterinary Medical Imaging and Small Animal Orthopaedics, Faculty of Veterinary Medicine, Ghent University, Salisburylaan, Belgium; 2 Department of Surgery and Anaesthesia of Domestic Animals, Faculty of Veterin- ary Medicine, Ghent University, Salisburylaan, Belgium; 3 Department of Medical Imaging, Faculty of Veterinary Medi- cine, University of Liege, Sart-Tilman; Belgium Keywords Equine, metacarpophalangeal joint, meta- tarsophalangeal joint, radiography, Warm- blood stallion Summary Objectives: To describe the radiographic ap- pearance of the dorsoproximal aspect of the sagittal ridge of the third metacarpal/metatar- sal bone in Warmblood horses. Methods: The lateromedial radiographic pro- jections of the metacarpo-/metatarsophal- angeal 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 lu- cency. 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. Vet Comp Orthop Traumatol 2010; 23: 411–416 doi:10.3415/VCOT-09-12-0130 Received: December 22, 2009 Accepted: May 13, 2010 Pre-published online: September 9, 2010 Correspondence to: Stijn Hauspie, DVM Faculty of Veterinary Medicine Ghent University Department of Veterinary Medical Imaging and Small Animal Orthopaedics Salisburylaan 133 9820 Merelbeke Belgium Phone: +32 09 264 7640 Fax: +32 09 264 7657 E-mail: Stijn.hauspie@ugent.be Funding: Stijn Hauspie is a research fellow of the “Special Research Fund”, Ghent University (Belgium). Results: In area I, 51.5% of the ridges appear- ed 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 sus- pected. In area II, 90.6% of the metacarpo-/metatar- sophalangeal joints were normal, 6.2% were irregular, 2.9% showed a depression or lucen- cy, and the sagittal ridge in 0.2% was flat- tened. A fragment was present in 0.3%, and suspected in 0.4%. Clinical significance: Morphological vari- ation is present at the dorsal aspect of the metacarpo-/metatarsophalangeal joint in young Warmblood stallions. These various as- pects should be recognised and described in horses presented for prepurchase examin- ation. However, their clinical relevance in the individual horse is unclear and needs further investigation. Introduction The dorso-proximal aspect of the equine metacarpo-/metatarsophalangeal joint is composed of a thick joint capsule, includ- ing a synovial pad, a layer of cartilage, sub- chondral bone, a synovial membrane and synovial fluid (1–3). Although the exact function of the synovial pad has not been studied, its location and structure suggest that it acts as a contact interface or cushion between the proximal dorsal rim of the proximal phalanx and the dorsal surface of the distal third metacarpal/metatarsal bone (MCIII/MTIII) during full extension of the fetlock joint (4). This anatomical region can be affected by specific disorders (e. g. osteochondrosis or chronic proliferative synovitis in the metacarpophalangeal joint), or it can be involved in a generalised joint disorder (e. g. capsulitis or synovitis, osteoarthritis, infectious or traumatic ar- thritis) (5, 6). An examination is frequently performed prior to the sale of a horse in order to assess the suitability of the animal for the purpose for which it is required. Depending on the intended use and value of the animal, a radiographic examination may be part of the examination. If a decision is made to take radiographic images, then projections of the metacarpo-/metatarso-phalangeal joints will be included (7). Should the vet- erinarian make a mistake in interpreting the radiographic images, the economic and legal consequences may be disastrous (7). However, there is a general lack of published information regarding the clinical signifi- cance of many radiographic findings, as well as the acceptable anatomical variations