Fig. 1. Location of the 1-cm-long skin incision with single suture, posterior to the L4 transverse process and 0.5 cm from the midline. The two injection sites for subcutaneous bupivacaine are shown by  arrows . The  broken-line oblongs are drawn on the skin at 1 and 2 cm distance with the same template that marks the incision line, all while the rat is under sevoflurane anesthesia.