High-resolution ultrasonography was performed on 14 patients with soft tissue swelling of the wrist and hand. The examination was done using a real-time 10-MHz sector probe placed directly on the lesion. The sonographic image could always demonstrate the liquid nature of cystic lesions. In recent ganglia, the fluid content was anechoic, and the cystic walls were rather thin; in some older lesions, irregular internal echoes and thicker walls were found. Rather often, multiple ganglia were observed, grouped in clusters. The presence of a liquid-filled duct directed to the articular space was demonstrated in 8/11 cases (73%). This finding is considered a diagnostic characteristic of ganglia, and it is very useful for correct surgical planning. In extensor cystic tenosynovitis, the echographic picture was quite different: the anechoic cavity was longitudinal in shape, following the tendon sheath, and the communicating duct was absent. Finally, the sonographic pattern of one case of de Quervain's disease was analyzed and discussed.