The lower trapezius myocutaneous flap based on the descending branch of the transverse cervical artery is particularly useful in the repair of defects over the back, shoulder and scalp region. Three illustrative examples are given of the use of this particular flap. The precise definition of the vascular territory in the overlying skin can be shown by selective angiography and intra-arterial injection of PGE 1. An axial vascular territorial map has been constructed to show the anatomical distribution of the various dominant areas that supply the skin over the back.