A NEW EXPERIMENTAL-MODEL - THE VASCULAR PEDICLED CUTANEOUS FLAP OVER THE MID-DORSUM OF THE RAT

The cutaneous vascular anatomy of the mid-dorsum in the rat and its ro le in flap design was studied in the rat. The investigation consisted of anatomic dissection, methylene blue injection into the axial artery , and flap harvesting in live animals. Dissection and injection reveal ed that the mid-dorsum of the rat derives its blood supply largely fro m the 10th intercostal artery, here referred to as the middle dorsal a rtery, which originates from the lateral aspect of the thoracic aorta. The cutaneous vascular territory of the middle dorsal artery was defi ned as follows: the medial border, midline of the dorsum; the lateral border, midaxillary line; the cephalic border, a line joining the medi al and lateral borders midway between the level of the axilla proximal ly and 1 cm above the base of the rib cage distally; and the caudal bo rder, a line drawn midway between the latter point proximally and the anterior superior iliac spine distally. Both unilateral and bilateral vascular pedicled island cutaneous flaps were harvested in living rats based on and exceeding the vascular territory delimited by methylene blue injection. Flaps limited to this territory with intact middle dor sal arteries showed total survival, while oversized flaps underwent pa rtial necrosis peripherally. Because of its simplicity, reliability, a nd consistent vascularity, this flap has potential applications in the study of flap hemodynamics.