The accuracy of the high-resolution real-time ultrasonic examination of the flexor tendons of the fingers of the hand has been tested on the retrospective study of 27 patients treated surgically. The method is sensitive and specific in the rupture of the tendons (8 cases), except when the latter is partial. Ultrasound enables the discrimination between palmar masses developed extrinsically (8 cases) and those involving the tendons (4 cases). A fluid collection inside the tendon's sheath has been detected in all the 5 cases of tenosynovitis, without false positive. The post-operative follow-up of operated tendons is easier by ultrasound.