A new flap model in the rat: the pectoral skin flap.

The purpose of this study was to describe a new axial-pattern experimental flap model in the rat. Wistar rats weighing 200 to 250 g were used in the experiment. In 15 rats, the superficial anatomy of the ventral thoracic region was studied by anatomic dissection, dye injection, and microangiography, using 5 rats in each group. The anatomic studies revealed that the ventral thoracic skin derives its principal blood supply from the long thoracic artery--a branch of the common thoracic artery. Based on these anatomic studies, the pectoral skin flap model, pedicled on the long thoracic vessels, was created in the rat. The flap is bounded medially by the midsternal line, laterally by the anterior axillary line, and superiorly and inferiorly by transverse lines passing at the level of the suprasternal notch and the xyphoid process respectively. In 5 animals, bilateral flaps (N = 10) were raised and replaced in situ. In 15 animals, oversized flaps were created by extending the flap for both a greater width (N = 10) and length (N = 10). Although all the flaps limited to the cutaneous territory as described were found to survive totally, oversized flaps underwent partial necrosis distally. The authors conclude that the pectoral flap is a simple and reliable skin flap model for future biological and pharmacological study because it is very easy to raise, has a consistent vascular pedicle, and has well-defined borders with consistent landmarks.