Radiographic and Computed Tomographic Evaluation of the Carpal and Tarsal Joints in Apparently Healthy Donkeys

The current study was achieved to provide a detailed radiographic and computed tomographic anatomic reference of the carpal and tarsal joints in Donkey with evaluation of both radiography and computed tomographic modalities. 13 adult apparently healthy donkey were used. All limbs were disarticulated at the stifle joint in case of hind limbs and at the elbow joint in case of fore limbs. Both carpi and tarsi of each animal were subjected to computed radiography in three views; Dorsopalmar or dorsoplantar, lateromedial and dorsolateral palmaromedial oblique or dorsolateral plantaromedial oblique. Computed tomographic scanning was done in different planes; transverse, sagittal, dorsal and three dimensional planes. Both radiography and computed tomography modalities were evaluated concerning the time needed for the technique, resolution, cost and availability. The dorsopalmar view of the carpal joint showed three articulations; radiocarpal joint, middle carpal joint and carpometacarpal joint, as well as, the 1st carpal bone that appeared as a radio-opaque circular mass behind the 2nd carpal bone. Dorsoplantar view of the tarsal joint showed four levels of articulations and the 4th tarsal bone was superimposed with central tarsal bone and 3rd tarsal bone. Both 2nd and 4th metatarsal bones were superimposed. In the lateral view of the carpal joints, the joints were well defined but carpal bones of each row appeared superimposed. In the lateral view of the tarsal joint, the lateral and medial ridges of trochlea tali, sustentaculum tali and the trochlear groove were all apparent in this view. The dorsolateral palmaromedial oblique view showed that the 4th and the ulnar carpal were more apparent but the second metacarpal bone was totally superimposed with the 3rd metacarpal bone. The dorsolateral plantaromedial oblique view showed that the 4th metatarsal bone was well defined and wasn’t superimposed but the 2nd metatarsal bone appeared superimposed with the 3rd metatarsal bone. The computed tomographic scanning showed that the carpal canal was well delineated. The lateral and medial collateral tendons, long tendon of ulnaris lateralis muscle, flexor carpi ulnaris (tendinous part) and the flexor carpi radialis tendon had the same bright gray degree. The extensor carpi radialis, common digital extensor tendon and extensor carpi obliquus tendons had a bright gray shade and were well delineated on the dorsal surface of trochlea radii. In the tarsal joint, the long digital extensor tendon was well defined along all levels of the tarsal joint especially at the level of middle talus, proximal and distal intertarsal joints and tarsometatarsal joint. The lateral digital extensor tendon was well delineated at the level of proximal inetertarsal, distal intertarsal and tarsometatarsal joint. The computed tomography was better than radiography in contrast and spatial resolution but it needed much time and cost than the radiography.