Pelvic Vessels and Nerves Dr. Sama-ul-Haque Dr. Rania Gabr

Objectives Describe the origin, termination, course and branches of the internal iliac artery. Discuss the origin, site, relations, branches & their final distribution of the sacral plexus. Discuss the anatomy of the autonomic supply of the pelvic organs.

Internal Iliac Artery Common iliac artery divides in front of the sacroiliac joint into external and internal iliac arteries. The Internal Iliac Artery passes down into the pelvis. At the upper margin of greater sciatic foramen it divides into anterior and posterior divisions.

Internal Iliac Artery

The Posterior division supplies the: 1- Posterior abdominal wall The Posterior division supplies the: 1- Posterior abdominal wall. 2- Posterior pelvic wall. 3- Gluteal region. The Anterior division supplies the: 1. Pelvic viscera (Except Ovary). 2. Perineum. 3.Gluteal region. 4.Adductor (medial)region of the thigh. 5.The fetus (through the umbilical arteries)

Branches of the Anterior division of Internal Iliac Artery 1- Umbilical artery Gives the superior vesical artery The distal fibrous part of this artery becomes the Medial Umbilical Ligament. 2- Obturator artery: pelvic musc. , ms of med comp of thigh, nutrient arts. 3- Inferior vesical artery (Male) It supplies, the Prostate, inferior part of the bladder and the Seminal Vesicles. It gives the artery to the Vas Deferens.

Branches of Anterior division of Internal Iliac Artery 4- Middle rectal artery: supplies: Semin. vesicle, prostate (vagina), inf part of the rectum 5- Internal pudendal artery Leaves pelvis through greater sciatic foramen Enters perineum by passing through lesser sciatic foramen Enters into pudendal canal with pudendal nerve Supplies anal canal musculature, skin & muscles of perineum.

Branches of Anterior division of Internal Iliac Artery 6- Inferior gluteal artery: pelvic diaphragm, piriformis, QF, upper hamstrings,Glut. Max. and Sciatic nerve 7- Uterine artery (Female) Crosses the ureter superiorly Ascends in the layers of broad ligament of uterus Ends by anastomoses with ovarian artery 8- Vaginal artery (Female): dividesinto: 1- vaginal: to vagina 2-inferior vesical : to urinary bladder

Branches of Anterior division of Internal Iliac Artery

Visceral Branches (in Female) Vaginal artery: Replaces the inferior vesical artery. Uterine artery:. Crosses the Ureter superiorly and supplies the uterus & uterine tubes. (B) Ovarian artery: Arises from the abdominal aorta.

Branches of Posterior division of Internal Iliac Artery 1- Iliolumbar artery: ps. Major, quadr. Lumb, iliacus,and cauda equina 2- Lateral sacral artery: piriformis, erector spinae and skin over, str. In sacral canal 3-Superior gluteal artery: piriformis, gluteii, tensor fascia lata

Branches of Posterior division of Internal Iliac Artery

Venous Drainage The pelvis is drained: 1- Mainly by the internal iliac veins and their tributaries. 2- Superior rectal veins 3- Median sacral vein. 4- Gonadal veins. 5- Internal vertebral venous plexus

Nerve Supply of pelvis (A) Somatic: Sacral plexus From Ventral rami of a part of L4 & whole L5 (lumbosacral trunk) + S1,2,3 and most of S4. It gives Pudendal nerve to perineum (B) Autonomic: 1. Pelvic splanchnic nerves (From S 2 , 3 & 4) They are the Preganglionic parasympathetic nerves to pelvic viscera & hindgut.

2. Sympathetic: It is formed of: (a) Pelvic part of sympathetic trunks: They are the continuation of the abdominal trunks. They Descend in front of the ala of the sacrum & terminate inferiorly in front of the coccyx and form a single ganglion (Ganglion Impar). (b) Superior & Inferior Hypogastric plexuses. 2. Sympathetic:

Sacral Plexus Lies on the posterior pelvic wall in front of Piriformis muscle. Formed from: The anterior rami of 4th & 5th lumbar nerves The anterior rami of 1st, 2nd, 3rd & 4th sacral nerves 4th lumbar nerve joins the 5th lumbar nerve to form Lumbosacral Trunk

Sacral Plexus

Sacral Plexus

Autonomic Nerves

Autonomic innervation of the pelvic cavity is via four routes: 1- the sacral sympathetic trunks, 2- periarterial plexuses, 3- hypogastric plexuses: sup and inf, and 4- pelvic splanchnic nerves.

Autonomic Nerves

The prevertebral plexus enters the pelvis as two hypogastric nerves, one on each side, that cross the pelvic inlet medially to the internal iliac vessels. The hypogastric nerves are formed by the separation of the fibers in the superior hypogastric plexus, into right and left bundles. The superior hypogastric plexus is situated anterior to vertebra L5 between the promontory of the sacrum and the bifurcation of the aorta.

Superior and Inferior Hypogastric Plexus

When the hypogastric nerves are joined by pelvic splanchnic nerves carrying preganglionic parasympathetic fibers from S2 to S4, the pelvic plexuses (inferior hypogastric plexuses) are formed . The inferior hypogastric plexuses, one on each side, course in an inferior direction around the pelvic walls, medially to major vessels and somatic nerves. They give origin to the following subsidiary plexuses, which innervate the pelvic viscera: 1-the rectal plexus; 2-the uterovaginal plexus; 3-the prostatic plexus; and 4-the vesical plexus.

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