Equine palmar foot morphology: a comparison of two and three dimensional measurement techniques for evaluating soft tissue structures
B.A. Hampson, M.A. de Laat1, S. Collins, A. Chen and C.C. Pollitt
The Australian Brumby Research Unit, School of Veterinary Science, The University of Queensland, Queensland, Australia
1Earth, Environmental and Biological Sciences School, Science and Engineering Faculty, Queensland University of Technology, Brisbane, Qld, 4000
Reasons for performing study: Currently there is no validated method of quantifying the soft tissues (ST) in the palmar foot of horses. The quantification of these structures may be important in the selection of horses for work and sport and in enabling the prevention of common palmar foot pathology.
Objectives: To assess the validity of quantifying equine palmar foot ST using radiometric parameters.
Methods: A latero-medial radiograph was taken of the left forefoot of 15 horses (10 Thoroughbred (TB) and 5 feral). Four radiometric parameters were chosen to represent the ST area of the palmar foot. CT images of the feet were then acquired and 3-D models generated to allow ST volume calculations. Radiometric parameters were correlated with 3-D volume measurements to determine if radiometric measurements provided an accurate prediction of ST volume. Parameters were also compared between domestic and TB horses which were assumed to have different foot loading histories.
Results: A strong positive correlation was found between palmar foot ST volume and the radiometric parameter palmar process-heel bulb length (r=0.61, p=0.02). There was also strong positive correlation (r=0.62, p=0.01) between ST volume and distal phalanx palmar cortex length. There were no significant differences in ungual cartilage, dermis and total ST volume between TB and feral horse groups.
Conclusions: Digital radiography may be used to estimate the ST volume of the horses’ foot. The lack of difference in ST volumes between TB and feral groups and the strong relationship between ST volume and bone size suggests that volume changes may not occur in response to variable loading history.
Potential relevance: Knowledge of the normal range of radiometric ST parameters may be useful to predict foot health in pre-purchase assessment of horses and to assist with selection of horses for work and sport.