Cross-sectional area of the tendons of the tarsal region in Standardbred trotter horses

Reasons for performing study: The assessment of a normal range for cross‐sectional area (CSA) of tendons in the tarsal region is important in order to use them as reference values in the identification of pathological changes of dimensions. Objectives: To provide normal reference values for the CSA of the tendons of the tarsus of Standardbred trotter horses (STH) by means of ultrasonography. Methods: Transverse echographic images of the tendons were obtained at different levels proximodistally; these images were digitised and CSA values (mean ± s.d.) were obtained for each structure. Results: The largest structure corresponded with the lateral digital flexor/caudal tibial tendon complex at Level 1 and the smallest was the medial digital flexor tendon at Level 4. Almost all tendons showed a slight decreasing in their CSA when crossing the tarsus. Conclusions: The normal CSA values of tendinous structures in the tarsal region of the STH are reported. These data could be used as anatomical references. Potential relevance: The establishment of reference values could serve as a tool to discriminate between normal and abnormal dimensions of tarsal tendons in STH. Other horse breeds should need their own reference values.