Pelvic Innervations

Extract

[...] Pelvic Innervations Lumbosacral Plexus Surgical Anatomy of the Retroperitoneum, Kidneys, and Ureters; only the pelvic courses of its nerves are reviewed here. The iliohypogastric nerve travels between, and supplies, the internal oblique and the transversus muscles and pierces the internal and external oblique muscles 3 cm above the external inguinal ring to supply sensation over the lower anterior abdomen and pubis. The ilioinguinal nerve passes through the internal oblique muscle to enter the inguinal canal laterally. It travels anterior to the cord and exits the external ring to provide sensation to the mons pubis and anterior scrotum or labia majora. [...]

[...] The most caudal portion of the pelvic plexus gives rise to the innervation of the prostate and the important cavernosal nerves. After passing the tips of the seminal vesicles, these nerves lie within leaves of the lateral endopelvic fascia near its juncture with, but outside, Denonvilliers fascia. They travel at the posterolateral border of the prostate on the surface of the rectum and are lateral to the prostatic capsular arteries and veins. Because the nerves are composed of multiple fibers not visible on gross inspection, these vessels serve as a surgical landmark for the course of these nerves (the neurovascular bundle of Walsh). [...]

[...] The pelvic continuations of the sympathetic trunks pass deep to the common iliac vessels and medial to the sacral foramina and fuse in front of the coccyx at the ganglion impar. Each chain comprises four to five ganglia that send branches anterolaterally to participate in the formation of the pelvic plexus. Presynaptic parasympathetic innervation arises from the intermediolateral cell column of the sacral cord. Fibers emerge from the second, third, and fourth sacral spinal nerves as the pelvic splanchnic nerves (nervi erigentes) to join the hypogastric nerves and branches from the sacral sympathetic ganglia to form the inferior hypogastric (pelvic) plexus. [...]