Arteries and Lymphatics of the Pelvis
The pelvis is home to the reproductive organs, which differ depending on gender. A complex system of blood vessels and arteries circulate blood throughout the region. The area also houses lymph nodes that facilitate the drainage of lymph.
The abdominal aorta branches into the right and left common iliac arteries at the level of the 4th lumbar vertebra. The common iliac arteries descend to the pelvic brim, where they divide into the external and internal iliac arteries.
The external iliac arteries leave the abdominal cavity to supply the lower extremities. They have two branches, the inferior epigastric and deep circumflex iliac arteries.
The internal iliac artery enters the pelvis to supply blood to pelvic organs, gluteal muscles, and the perineum. It has many branches that stem from its two divisions (anterior and posterior):
Umbilical artery and superior vesical artery: Supply the upper part of the bladder
Obturator artery: Runs along the lateral pelvic wall and supplies pelvic muscles, ilium, and head of the femur
Inferior vesical artery: In males only; supplies blood to the base of the bladder and gives rise to the prostatic artery that supplies blood to the prostate, seminal glands, and the artery of the vas deferens, which supplies blood to the vas deferens
Middle rectal artery: Supplies blood to the rectum
Internal pudendal artery: Enters the perineum through the lesser sciatic foramen; supplies blood to the anal muscles, the skin and muscles of the perineum, and dorsal artery to the penis and clitoris; also gives rise to the inferior rectal artery
Inferior gluteal artery: Also runs through the greater sciatic foramen and supplies blood to the piriformis, coccygeus, levator ani, and gluteal muscles
Uterine artery: Runs medially on the floor of the female pelvis and then crosses the ureter to reach the broad ligament; supplies blood to the ureter, uterus, uterine tube, ovary, and vagina; has a branch called the vaginal artery that replaces the male inferior vesical artery
The posterior division of the internal iliac artery supplies blood to the pelvic wall and the gluteal region:
Iliolumbar artery: Ascends in front of the sacroiliac joint to supply blood to the iliacus and psoas major, quadratus lumborum muscles, and the cauda equina
Lateral sacral arteries: Descend in front of the sacral plexus and provide blood to the piriformis and vertebral canal
Superior gluteal artery: Leaves the pelvis through the greater sciatic foramen and supplies blood to the gluteal muscles and tensor fascia latae
The remaining arteries also supply blood to various organs of the pelvis:
Superior rectal artery: A continuation of the inferior mesenteric artery in the abdomen; supplies blood to the rectum and anal canal
Median sacral artery: Starts at the bifurcation of the aorta and runs down to the front of the sacrum and coccyx
Ovarian arteries: In females only; start at the abdominal aorta around the level of the 1st lumbar vertebra and run down behind the peritoneum and enter the suspensory ligaments of the ovaries
The masculine counterpart of the ovarian arteries are the testicular arteries, but they go through the inguinal canals and do not enter the pelvis.
The principal veins that return blood from the pelvis include the external and internal iliac veins and the median sacral veins. They accompany the arteries of the same names.
Lymphatics in the pelvis
Several groups of lymph nodes are located along the vessels in the pelvic region:
External iliac lymph nodes: Receive lymph from the inguinal lymph nodes, which are located along the femoral vein in the anterior thigh, and from pelvic organs
Internal iliac lymph nodes: Receive lymph from the pelvic organs, perineum, and gluteal region
Sacral lymph nodes: Receive lymph from the pelvic organs and drain into the internal or common iliac nodes
Common iliac lymph nodes: Receive lymph from the other pelvic nodes
Pararectal nodes: Lie in the connective tissue next to branches of the internal iliac lymphatic vessels
Superficial inguinal and deep inguinal nodes: Drain lymph from the inferolateral part of the trunk and perineum
Lumbar nodes: Associated with the aorta and inferior vena cava; receive lymph from the previously listed nodes
The lymph nodes of the pelvis are interconnected quite extensively, which means some of the nodes can be removed without disturbing lymphatic drainage. However, it also means cancerous cells can easily spread to any pelvic or abdominal organs.