The authors report a new local combined flap involving the distally based Latissimus dorsi muscle pedicled on the lumber perforating arteries and prolonged by the last three digitations of the Serratus anterior muscle supplied by the thoracic branch of the thoraco-dorsal artery. This artifice, never previously described, increased the bulk and arc of rotation of the dorsalis flap. It was thus possible to cover a wide defect on the posterior aspect of the sacro-iliac region in a patient previously operated for a highly malignant histiocytofibroma. The anatomic considerations, harvesting technique and advantages and drawbacks of this flap are discussed.