COMPUTERIZED BONE-DENSITY ANALYSIS OF THE PROXIMAL PHALANX OF THE HORSE

This study utilized computed tomography to determine the density patte rns and the subchondral bone thickness of the first phalanx of the hor se. An image processing system and commercially available software wer e used to process the computed tomographic slices obtained from the fi rst phalanges of a 2-year-old Thoroughbred horse. The thickness and de nsity of the medial and lateral cortices in the mid-shaft of the bone were similar; however, the cortex on the dorsal aspect was more dense and extended farther toward the proximal and distal aspects of the bon e than the cortex on the palmar aspect. Density of the cortical bone w as highest at the region of the bone with the smallest diameter. The c ortical bone density at mid-shaft was approximately 3.5 times the canc ellous bone density at the proximal aspect and 2.5 times that at the d istal aspect of the bone. A moderate correlation (r = 0.53, p < 0.01) was found between the subchondral bone density and thickness. Despite limited numbers of specimens used, this study demonstrated the potenti al applications of computed tomography for investigating equine joint mechanics and diseases.