The latissimus dorsi musculocutaneous flap has proven utility in the reconstruction of defects of the breast, chest wall, head and neck, and upper extremity. As a free flap, the latissimus dorsi has become a mainstay for the coverage of severe traumatic tibial/ fibular wounds. We describe a new and useful extension of the latissimus dorsi musculocutaneous unit that consists of a fasciocutaneous segment based on musculocutaneous perforators from the thoracodorsal artery. The vascular anatomy of the flap is described and illustrated with 6 fresh human cadaveric dissections. We also present 3 cases in which in vivo dissections of this flap were performed, 2 at the time of latissimus microvascular transfer and 1 approximately 5 days after microvascular transfer to salvage exposed fractured tibial bone successfully due to distal muscle loss. A pedicled or free latissimus dorsi musculocutaneous flap may be reliably extended and thereby rendered more versatile through the use of the perforator-based fasciocutaneous flap. Benefits and potential applications of the latissimus dorsi perforator-based fasciocutaneous flap are discussed.