Radiographic localization of the attachments of soft tissue structures in the tarsal region of horses

OBJECTIVE To identify radiographic locations of soft tissue attachments in the tarsal region of horses and describe any variability in the gross anatomy of those attachments. SAMPLE 15 cadaveric limbs from 8 adult horses. PROCEDURES 8 limbs were used for dissection and radiography of soft tissue structures, with metallic markers used to identify radiographic locations of soft tissue attachments. The remaining 7 limbs were used to evaluate anatomic variations in the insertion of the tendon of the fibularis tertius muscle. A consensus list of preferred radiographic views for evaluating each soft tissue attachment was created. RESULTS The dorsoplantar, dorsoproximolateral-plantarodistomedial oblique (35 degrees proximal and 45 degrees lateral), dorsoproximomedial-plantarodistolateral oblique (10 degrees proximal and 15 degrees medial), and plantaroproximal-plantarodistal oblique (70 degrees proximal; flexed) views were preferred for evaluating the collateral ligaments. The standard oblique views and plantaroproximal-plantarodistal oblique (70 degrees proximal; flexed) view were preferred for evaluating the tendinous attachments of the gastrocnemius and superficial digital flexor muscles. All 4 standard views were necessary for evaluating the tendinous attachments of the cranial tibial and fibularis tertius muscles, the dorsal tarsal ligament, and the origin of the suspensory ligament. Three configurations of the insertion of the fibularis tertius tendon were identified grossly. In limbs with osteoarthritis of the distal tarsal joints, the dorsal tarsal ligament firmly adhered to the centrodistal tarsal joint. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that attachments of soft tissue structures in the tarsal region of horses were in distinct radiographically identifiable locations and that visualization of individual soft tissue attachments could be optimized with certain radiographic views, including some nonstandard views.