ABSTRACT
The lower one-third point of a line connecting the posterior superior iliac spine and the middle of the lower margin of the ischial tuberosity is used as the acupuncture point to the pudendal nerve. The present study anatomically examined the positional relation between a needle inserted in the acupuncture point and the pudendal nerve as well as examined the projection region of the nerve to the body surface, using the bilateral pudendal nerves of 18 Japanese cadavers.<br>The needle inseted in the acupuncture point to the pudendal nerve missed the nerve caudally or laterocaudally in many cases, but with twelve cases directly pricking the caudal portion of the nerve. The pudendal nerve lying on the sacrospinous ligament was projected just on or lateral to a line connecting the posterior superior iliac spine and the medial edge of the lower margin of the ischial tuberosity, and in rostro-caudal direction the pudendal nerve was situated in a range 50 to 60% from the top of that line. The height of the sacral cornua corresponded to that of the rostral half of the pudendal nerve lying on the sacrospinous ligament or that more rostral than the rostral tip of the nerve, and the height of the lower tip of the coccyx corresponded to that more caudal than the caudal tip of the nerve.