Transfer of segmentally split pectoralis major for the treatment of irreparable rupture of the subscapularis tendon

Irreparable ruptures of the subscapularis tendon represent a difficult surgical problem. An accepted treatment has been to utilize the pectoralis major as a transfer, using the superior half of the tendon, which involves parts of both the sternal and clavicular heads of the muscle. We undertook an anatomic study to investigate the possibility of using a segmentally split pectoralis transfer of the sternal portion alone, which may provide a transfer with a vector more closely matching that of the functioning subscapularis muscle. From 22 dissected cadaveric shoulders, it was possible in all cases to obtain a segmentally split tendon suitable for transfer. We describe the morphology of the pectoralis major musculotendinous unit and neurovascular structures pertinent to the performance of a safe and effective transfer.