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 CSAvalues (means.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 CSAvalues 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.