[Significance of the arterial supply for the formation of the pectoralis major island flap].

With arteriograms and cadaver dissections we found some variations of the artery with the consequence that three different pectoralis major flaps could be designed: 1. A broad based flap with a very short artery, 2. an island flap with one long vascular bundle in the middle part of the muscle, 3. two alternatives flaps where there are two vascular bundles, nurturing different parts of the muscle. In most instances the artery runs in the midclavicular line under the clavicle before it penetrates the mid-portion of the PM-muscle. In more than 90% we found a very short thoracoacromial artery and a consequently early ramification of the arterial vessels. In this case one can take either a medial or lateral part of the sternocostal portion of the pectoralis major muscle. In other cases we found a late ramification of the pectoral artery. In these cases we cannot divide the middle portion of the muscle as just described. On the other hand, we found also cases of a short artery where a broad based flap is necessary. In one case we found a common trunk of thoracoacromial and thoracodorsal artery lateral to the midclavicular line. We now first identify the vessels by incising in the midclavicular line. In most cases it is logical not to incise the clavicular portion of the muscle but only to separate this part from the bone to identify the nurturing vessels. In about 95% one can take an island flap with a long vascular bundle surrounded by adipose tissue, preserving the clavicular portion of the PM-muscle.