Introduction: Mapping the branching patterns of the thoracoacromial artery has a particular practical importance. Familiarity with the different anatomical variations is essential for successful surgical procedures in the anterior shoulder region. Case presentation: We present an unusual anatomical variant observed during the dissection of a cadaver at the Department of Anatomy and Embryology of the “George Emil Palade” University of Medicine, Pharmacy, Science and Technology of Târgu Mureş, Romania. According to the classical description, the thoracoacromial artery originates from the second part of the axillary artery, but we observed an unusual branching variation: the thoracoacromial artery provided a subscapular branch right after its origin, then it split into a pectoral branch, the lateral thoracic artery, and a common trunk that gave a second pectoral branch and a deltoid-acromial branch. The clavicular branch was missing. Conclusions: The case we presented demonstrates that there are anatomical variations of the axillary artery system that are partially or entirely different from the classical descriptions. Our study describes a variation of the thoracoacromial artery that has not been reported so far.