Figure 43-8 Spinal needle tip designs: Quincke (left), Sprotte (middle), and Whitacare (right). Scanning electron micrograph. (Adapted from Puolakka R, Andersson LC, Rosenberg PH: Microscopic analysis of three different spinal needle tips after experimental subarachnoid puncture. Reg Anesth Pain Med 25:163–169, 2000.)