The thoracodorsal system represents a versatile, yet reliable system for the harvest of tissues for microsurgical transplantation. Also, the donor vessel anatomy is generally thought to be highly predictable in terms of topography and branching patterns. In this article we describe for the first time the occurrence of a branching pattern during a clinical harvest of the latissimus dorsi muscle flap, previously encountered only in cadaver dissections. We compare our intraoperative findings with published anatomical investigations and discuss the implications of this particular variation of the blood supply to the latissimus dorsi muscle for clinical practice.