Objective
To evaluate the usefulness of the diagnostic ultrasound (US) to diagnose carpal tunnel syndrome (CTS) and the correlation between electrodiagnosis and US findings.

Method
Forty hands of 30 patients diagnosed with CTS by electrodiagnosis and 28 hands of 19 controls were examined with US. The 7.5 MHz probe of the US was used to view the median nerve in the carpal tunnel. The short and the long axis and the area at the two points, 2 cm proximal and 1 cm distal to the distal wrist crease were measured. The flattening and compression ratio and the ratio of the area in both groups were analysed. The correlation between the eletrodiagnostic severity and compression ratio were analyzed.

Results
The compression ratio of CTS was significantly increased comparing with that of control group. The compression ratio of severe CTS was significantly increased comparing with that of mild and moderate CTS.

Conclusion
These results suggest that US is useful in diagnosis of CTS.