Variability in the vascularity of the pectoralis major muscle

Although the pectoralis major muscle has been the subject of numerous anatomic studies over the past 20 years, there remains a high complication rate for pedicled pectoralis musculocutaneous flaps. In this report, angiograms of 43 pectoralis major muscles were studied to assess the vascular territories of its three arterial supplies: lateral thoracic artery, the pectoral branch of the thoracoacromial artery, and the anterior intercostal perforators of the internal mammary artery.

Twenty-two adult human cadavers underwent whole-body arterial perfusion (200 mL/kg) with a mixture of lead oxide, gelatin, and water through the carotid artery. All pectoralis major muscles were dissected and radiographed. Radiographs were photographically printed as contact prints. The vasculature of each muscle was analyzed using the paper template technique.

The pectoral branch of the thoracoacromial artery supplied 50.7% of the vascular territory of the pectoralis major. The lateral thoracic artery was present in 37 of 43 angiograms and supplied a mean territory of 6.6%. The anterior intercostal perforating branches of the internal mammary artery supplied 43% of muscle parenchyma. There was considerable variability in the extent of various vascular territories from muscle specimen to specimen.

Despite excellent surgical technique, certain pedicled musculocutaneous pectoralis major flaps may suffer partial distal necrosis simply owing to the relatively small vascular territory of the pectoral branch of the thoracoacromial artery.