Figure 58-10 Relationship between patient weight and height and block height during spinal anesthesia with 12 mg hyperbaric bupivacaine in 50 term parturients undergoing cesarean section. Circles represent one patient; squares, two patients; triangles, three patients; and diamonds, four patients. (From Shnider SM, Moya F: Effects of meperidine on the newborn infant. Am J Obstet Gynecol 89:1009–1015, 1964.)