Needle electrode insertion into tibialis posterior. A new approach.

The tibialis posterior can be a valuable muscle in the electrodiagnostic evaluation of the sacral plexus, lumbosacral roots, lower extremity neuropathies and tibial nerve lesions. It may be under utilized, however, because it is generally considered to be inaccessible to needle examination. The purpose of this study was to compare the widely recommended posterior approach to this muscle to an anterior approach that we define. In six cadaver legs, the safe access to this muscle via the anterior approach was 16.8 +/- 5 mm by contrast to 9.5 +/- 2 mm by the posterior approach. We conclude that the anterior approach to needle electromyography of the tibialis posterior muscle is easier, safer and deserves more widespread practice.