Bowstring injury of the flexor tendon pulley system: MR imaging

OBJECTIVE. The flexor tendon pulley system is often ruptured when a flexed finger is forcibly extended. In the acute phase, soft-tissue swelling and pain often make clinical evaluation difficult. These pulleys are not constantly visualized on MR imaging. Rupture of the pulley system can be inferred by observing bow stringing of the underlying flexor tendons when MR imaging is obtained with the finger in flexion. Our objective is to describe the flexor tendon pulley system and present our MR technique.