How is lateral recess injection located on the body surface

Under strict aseptic operation, 16G puncture needle was used to perform the operation according to the method of lumbar epidural puncture and catheterization, and attention was paid to make the needle tip slightly inclined to the affected side. After confirming the success of epidural puncture, the oblique Angle of the needle tip was adjusted to the affected side, and the epidural catheter was inserted, so that the catheter could enter the recess of the affected side along the lateral space of the epidural space along the arc of the needle tip. At this time, there could be numbness in the lower limb of the affected side. The experimental dose of 2% lidocaine was quickly injected into the catheter after the withdrawal of the catheter with no blood or fluid, and the expected positioning epidural block effect was observed 5 to 15 minutes later, but the signs of "spinal anesthesia" were not observed, and the therapeutic drugs were given again. Finally, the puncture needle and catheter were withdrawn and observed for 5 to 10 minutes. That's the way we do it, and there are good ways that I want you to discuss