An epidural is best performed with the patient sitting because that position maximizes the flexion of the spine and optimizes the openings between the spinous processes . A second choice would be to have the patient lying laterally with the knees and head maximally flexed toward the abdomen. L_2–3 or L_3–4 are the ideal interspaces for performing the block, but it can also be performed at L_4–5 or L₅–S₁, either in the midline or via a lateral approach. With the back prepped and draped, the anesthesia provider should inject a liberal dose of 1–2 % lidocaine at the chosen interspace, including the deeper tissues as well as the skin. If adequate local anesthesia is used, the remainder of the procedure should not be painful or even uncomfortable. A 19 g Huber-tipped, Tuohy, or similar needle is inserted in the midline, staying as close to the upper spinous process of the chosen interspace as possible, and directing the needle slightly cephalad. If bony tissue is encountered, move the needle more to the center of the interspace and continue to direct it slightly cephalad. If that is unsuccessful then move to the bottom of the interspace or move to another interspace.