Representative muscle activity waveforms. APB, abductor pollicis brevis; ECR, extensor carpi radialis; EDC, extensor digitorum communis; FCU, flexor carpi ulnaris; FDI/SDI/TDI, first/s/third dorsal ...

[1] The mechanism of injury is thought to be forceful extension of a flexed digit. Avulsion of an isolated flexor digitorum superficialis (FDS) tendon is rare, and the exact pathology is uncertain.