Figure 2.
Transmission of labor pain. Labor pain has a visceral component and a somatic component. Noxious impulses from the uterus and cervix follow afferent sensory-nerve fibers that accompany sympathetic nerves, traveling through the paracervical region and the pelvic and hypogastric plexus to enter the lumbar sympathetic chain and the dorsal horn of the spinal cord through the white rami communicantes of the T10, T11, T12, and L1 spinal nerves. Noxious impulses from the vagina and perineum travel via the pudendal nerve to enter the spinal cord at S2 to S4. Reprinted with permission from Eltzschig HK, Lieberman ES, Camann WR. Regional anesthesia and analgesia for labor and delivery. N Eng J Med. 2003;348(4):319–332.136 Copyright © 2003 Massachusetts Medical Society. All rights reserved.