Cadaveric study of methods for subscapularis muscle needle insertion

Objective: To evaluate the accuracy for three methods for needle insertion into the subscapularis muscle for electromyography, botulinum toxin injection, and phenol nerve block. Design: Three needle insertion methods were evaluated by cadaver injection by an American Board of Electrodiagnostic Medicine certified physician. An anatomist, blinded to the method used, served as the dissector to evaluate the effectiveness of the methods tested. Results: A posterior axillary approach was most effective for needle insertion into the subscapular muscle compared with a medial scapular or a superior scapular approach. No approach was ideal for subscapular nerve injection. Conclusions: A posterior axillary approach is best for needle insertion of the subscapularis muscle for electromyography or botulinum toxin injection. Subscapular nerve injection is difficult from all of the three approaches tested.