Abstract
Surgical extirpation of advanced cancers of the head and neck almost always requires extensive resections that invariably necessitate some sort of large flap for reconstruction. In recent years immediate oneโstage reconstruction of large defects in the area of the tonsillar fossa and the pharynx have been facilitated by the development of myocutaneous flaps, especially the pectoralis major myocutaneous flap. With this flap, immediate oneโstep reconstruction at the time of the initial operation is accomplished. Myocutaneous flaps, however, require more skill and concentration in their elevation than do skin flaps in order to preserve the axial feeder vessel running along the underside of the muscle and supplying the allโimportant perforating vessels to the overlying muscles and skin. We have noticed a constant perforating vessel, approximately 2โcm long, coming off the pectoral branch of the thoracoacromial artery medial to the cephalic vein and 2 cm below the border of the clavicle. This pierces the substance of the overlying pectoralis major muscle and runs anteriorly into the subcutaneous fatty hypodermal layer. This vessel accurately localizes the position of the proximal portion of the pectoral branch of the thoracoacromial artery before elevation of the pectoralis major muscle has been started. The imaginary line joining this vessel and the island skin flap allows simplicity in elevation of the muscle pedicle and obviates fear of transecting the arterial supply to the skin island during the dissection. We have found the vessel to be present in 26 consecutive cases over the last 12 months. We present our findings of a sentinel vessel localizing the pectoral branch of the thoracoacromial artery as a guide in liberating the muscular paddle and axial artery in elevation of pectoralis major myocutaneous island flaps.