BACKGROUND Ischaemic flap complications can be a problem following harvest of the latissimus dorsi (LD) musculocutaneous flap or thoracodorsal artery perforator (TAP) flap. We investigate the reliable locations of the perforators of the thoracodorsal artery. METHODS Twenty latissimus dorsi flaps harvested from cadavers were used in the study. In fifteen flaps the thoracodorsal artery was injected with coloured latex, and the locations of perforators were recorded. In five flaps perfusion of the skin paddle was evaluated using 3D CT angiography following injection of the thoracodorsal artery with a barium sulphate/gelatin mixture. RESULTS At least one perforator originating from the descending branch of the thoracodorsal artery was found in all specimens, whereas no perforators from the transverse branch were found in 33% of flaps. At least one perforator originating from the descending branch in all flaps was found between 9.5 and 15.4 cm from the posterior axillary fold, within 4.3 cm of the lateral border of the latissimus muscle. 58% of all perforators from the descending branch, and 39% of all perforators from the thoracodorsal artery were found in this region. CT scanning of the hemiback flaps demonstrated contrast in the superior two-thirds. Perfusion of the skin paddles in three locations was demonstrated- superior transverse (bra strap), vertical and lower transverse. CONCLUSIONS Thoracodorsal artery perforators could be found within a reliable region. Positioning of the TAP flap skin paddle over this region will maximise the chances of including a perforator and may reduce the risk of ischaemia. For a musculocutaneous LD flap, the skin paddle can be in any of the 3 popular locations, i.e. upper transverse, vertical and lower transverse, as they were shown to be well vascularised.