High-resolution ultrasonography of the carpal tunnel.

Twenty-eight wrists of 25 patients with carpal tunnel syndrome (CTS) and 28 wrists of 14 normal control subjects were studied with high-frequency real-time ultrasonography. Three general findings could be observed in CTS, regardless of its cause: swelling of the median nerve at the entrance of the carpal tunnel; flattening of the median nerve in the distal carpal tunnel; and increased palmar flexion of the transverse carpal ligament. Quantitative analysis proved these findings to be significant. We conclude that high-resolution sonography is able to diagnose median nerve compression in the carpal tunnel syndrome and to detect some of its potential causes.