The gross and histologic anatomy of the myotendinous portion of the supraspinatus muscle was investigated with coronal and sagittal sections from 20 anatomic specimen shoulders. The anterior lateral portion of the supraspinatus contained more tendon than the posterior portion of the muscle in all 20 specimens. In seven specimens there were separate muscle fibers that originated from the most anteromedial area of the supraspinatus fossa. Knowledge of this anatomy aids in magnetic resonance image interpretation and open or arthroscopic evaluation of the supraspinatus. This consistent tendinous portion may be useful in rotator cuff repair and may provide a firm area for suture closure of the rotator interval. This prominent anterior tendinous area may serve to protect the supraspinatus during anterior forward flexion motion through the impingement arc.
From the Department of Orthopaedics, University of Southern California Keck School of Medicine, Los Angeles, CA.
Reprint requests to C. Thomas Vangsness, Jr., MD, 1510 San Pablo Street, Suite 322, Los Angeles, CA 90033.
Received: June 19, 1998.
Revised: December 23, 1999; May 30, 2000.
Accepted: June 6, 2000.