Shared Distal Insertion of the Gluteus Medius and Piriformis Muscles and Implications for Rehabilitation Exercises

Abstract

Motivation for this study was prompted by the discovery of bilateral shared tendinous insertion of the gluteus medius (GM) and piriformis (PM) muscles into the anterior trochanteric crest during routine dissection of the gluteal region of a 58-year -old male cadaver. We therefore asked, what is the frequency of GM and PM shared insertions into the greater trochanter, and how could this impact physical therapy interventions for piriformis syndrome? In 23 specimens from either side of 16 embalmed human cadavers, we dissected and characterized the detail of GM and PM insertions. We discovered that just over 50% of the specimens dissected exhibited shared tendinous insertions between the two muscles, and in one specimen, we observed additional fusion of fibers of the superior gemellus (SG) and obturator internus (OI) muscles into the PM. The distal attachments of the GM and PM are more complex than traditionally understood and should be considered when prescribing rehabilitation exercises to treat piriformis syndrome.