Radiogrametric Analysis of the Thoracic Limb Phalanges in Arabian Horses and Thoroughbred Horses.
Authors: Gündemir Ozan, Szara Tomasz, Pazvant Gülsün, Erdikmen Dilek Olğun, Duro Sokol, Perez William
Journal: Animals : an open access journal from MDPI
Summary
Radiographic morphology of forelimb phalanges differs meaningfully between Arabian and Thoroughbred horses, according to analysis of latero-medial digital radiographs from 25 Arabian and 50 Thoroughbred horses, suggesting breed-specific skeletal characteristics that could inform lameness diagnosis and farriery assessment. The researchers used nine direct measurements and three derived indices from the proximal, middle, and distal phalanges, finding that the depth of the proximal phalangeal head proved most discriminatory between breeds, correctly classifying 89.33% of samples, whilst the middle phalanx achieved 77.33% accuracy and the distal phalanx only 54.67%. Sexual dimorphism was minimal in Thoroughbreds across all parameters, but Arabian mares exhibited significantly greater lengths in the proximal and middle phalanges compared to stallions (p < 0.05 to p < 0.001). The distal phalanx showed negligible variation, both between breeds and sexes, suggesting this bone contributes little to breed differentiation and may be more conserved across equine types. These findings have practical value for practitioners interpreting radiographs or considering breed-specific biomechanical factors in lameness work-ups, though the modest classification accuracy for middle and distal phalanges indicates that digital radiographs alone cannot reliably distinguish breeds without considering other skeletal regions.
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Practical Takeaways
- •Radiographic measurements of proximal and middle phalanges can be used to differentiate between Arabian and Thoroughbred horses with moderate to high accuracy (77–89%), which may be useful in breed verification or disputed ownership cases
- •Sexual dimorphism in digital bone morphology is breed-dependent; farriers and veterinarians should not assume uniform sex-related size differences across all horse breeds
- •Distal phalanx measurements have limited clinical utility for breed or sex discrimination, suggesting morphological variation in this bone is less breed-specific than in proximal structures
Key Findings
- •Thoroughbred horses showed no significant sexual dimorphism in forelimb phalanges, while Arabian horses displayed significant differences between sexes in proximal and middle phalanx measurements (p < 0.05 and p < 0.001)
- •Discriminant analysis correctly classified 89.33% of proximal phalanx samples to breed, 77.33% of middle phalanx samples, and only 54.67% of distal phalanx samples, indicating breed-specific morphology in proximal bones
- •The depth of the caput of the proximal phalanx was the critical discriminating measurement between Arabian and Thoroughbred horses
- •Distal phalanx measurements were insignificant between breeds and sexes, limiting their diagnostic value for breed or sex differentiation