The research in the vascularisation of myocutaneous flaps of the pectoralis major muscle was conducted on the human cadavers. After the injection of the arteries 20 myocutaneous flaps were created. The main artery which is the source of vascularization of this muscle is pectoralis branch of thoraco-acromial artery. The objective of the research was to find out the direction of run of this artery. The direction variability was defined. The variability in the run of the branch of the thoraco-acromial artery refers to the place of departure from the thoraco-acromial artery, does not influence usefulness of the pectoral major muscle in creating the myocutaneous flap, considering the constant pathway of run of the distal part of this artery. The results of our research was compared with the classical description of the vascularisation given by the creator of this flap as well as with the works of authors dealing with the same issue.