Sonographic appearance of nontraumatic tear of flexor carpi radialis muscle-a case report.

We present an unusual case of a man with a nontraumatic tear of the flexor carpi radialis muscle after a regular swimming exercise, without known precipitation factors. The muscle tear was diagnosed by ultrasonography, which showed a cystic mass with increased peripheral vascularity, and was confirmed by magnetic resonance imaging. After conservative treatment, follow-up ultrasonography showed resolution of the hematoma. The patient was able to continue swimming without pain or limitation of function.