The most frequently injected upper-limb muscles were flexor carpi radialis (64.0% of patients), flexor carpi ulnaris (59.1%), flexor digitorum superficialis (57.2%), flexor digitorum profundus (52 ...

[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.