Gross and ultrasonographic anatomy of the carpal flexor tendon sheath in horses.

This study was undertaken to establish the gross anatomy and the ultrasonographic appearance of the carpal digital flexor tendon sheath (carpal sheath) and the palmar carpal region in normal horses. The isolated forelimbs from 15 horses were used to study the morphology of the sheath and associated structures, including a detailed study of the location of the main blood vessels and nerves in that region. These limbs and the forelimbs of five live, sound horses were also examined ultrasonographically. The examination yielded good soft tissue detail of the tendons and ligaments, synovial and perisynovial tissues and larger blood vessels. There was a good correlation between the ultrasonographic and gross anatomical appearance of the limbs. The sheath cavity was only identified after it had been distended with water, and the various synovial recesses at the level of the carpal canal were poorly imaged.