The expansive gluteus maximus flap.

The rich vascular network of the gluteal and posterior thigh region provides for a larger range of flaps for reconstructive surgery than previously described. Facility with these flaps requires an appreciation of relevant anatomy, embryology, and anthropology. Structural changes in the gluteus maximus muscle are critical to the evolutionary advance toward an upright stance during walking. The superficial and deep segmentation of the gluteus maximus are best appreciated by phylogenic and ontogenetic study. Femoral arterial and gluteal arterial anastomotic hemodynamics are affected by the relative involution of the gluteal system in late embryogenesis. The gluteal thigh flap should include contributions from the femoral system when the cutaneous branch of the inferior gluteal artery cannot be identified. Huge sacral wounds can be closed with gluteus maximus myocutaneous flaps with maintenance of muscular function by detaching the entire origin, sliding the muscle medially, and reconstructing these attachments. By dissection between the divergent inserting fibers of the gluteus maximus, a long, superficial portion of the muscle can be raised that forms the basis of the extended gluteus maximus flap. The pedicle of the flap is at the level of the piriformis muscle and the skin paddle can be placed over the midportion of the posterior thigh. Finally, the first deep femoral perforating artery forms the basis of a posterolateral fasciae latae flap that is well suited for coverage of defects over the trochanter.