<P> Pudendal anesthesia, also known as a pudendal block, or saddle block, is a form of local anesthesia commonly used in the practice of obstetrics to relieve pain during the delivery of baby by forceps . The pudendal nerve block prevents fainting during forceps delivery which was common before pudendal nerve block use was available . The anesthesia is produced by blocking the pudendal nerves near the ischial spine of the pelvis . The ischial spine separates the greater and lesser sciatic foramina at the exit of the bony pelvis . Pelvis in Latin means' saucepan' and one can view the bony human pelvis as a saucepan, with circular / cylidrical walls, but without a base and a flailed upper rim, or wings to which the gluteal muscles (hip bone stabilisers) attach . The pelvic bony cylindrical walls also have a curve, which follows that of the curve of the sacrum, the fused vertebral bones of the lower end of the spine . </P> <P> The pudendal block gets its name because a local anesthetic, such as lidocaine or chloroprocaine, is injected into the pudendal canal where the pudendal nerve is located . This allows quick pain relief to the perineum, vulva, and vagina . A pudendal block is usually given in the second stage of labor just before delivery of the baby . It relieves pain around the vagina and rectum as the baby comes down the birth canal . It is also helpful just before an episiotomy . Lidocaine is usually preferred for a pudendal block because it has a longer duration than chloroprocaine which usually lasts less than one hour . </P>

What structure is a reliable landmark for a pudendal nerve block