Ultrasonography is the best examination to explore the flexor tendons anatomy and disorders from the wrist to the digit. It is the only dynamic and comparative tool easily accessible for the surgeon. Indeed, ultrasonography is always available in all the departments of your hospital. Recent innovations permit to see superficially (high-frequency probes), precisely (smaller probes), and with greater softwares for an effective Doppler mode. Ultrasonography becomes a very important help at the outpatient clinic examination. In the future it can be used in the operating room to perform miniinvasive surgery under local anesthesia to control active motion of the gliding of flexor tendons.