Figure 3: The image below shows the procedure to insert the catheter on the dorsum of a rabbit (A, B and C) and distribution and testing time (D, E, F and G). To simplify the process, in this procedure the internal catheter is placed subdermally. To avoid additional injury to the exit site the catheter is placed without sutures. In second row, testing times and concentrations indicated that 1% methylene blue diffused into the epidermis, dermis and reached the panniculus muscle of the rabbit in the cadaver model. Over a 2 hour pumping period at 0.1 ul/min (D and E), the distribution of the dye formed a 1mm corona around the exit site. At 1 ul/min (F and G) the corona extended 2 mm with more methylene blue reaching the dermis. While the distribution around the epidermis always appears to be circular in shape, in the dermis the diffusion depends on the specific structural features of the tissue, and then the dye is present in irregular shapes. This distribution will obviously be different for other compounds.