The pelvic cavity contains the organs of reproduction, urinary bladder, pelvic colon, rectum and numerous muscles. Its arterial supply is largely via the internal iliac artery, with some smaller arteries providing additional supply. In this article we will look at the anatomy of the pelvic arteries, detailing their anatomical course, branches and their clinical relevance.
The internal iliac artery is the major artery of the pelvis. It originates at the bifurcation of the common iliac artery into its internal and external branches, as shown in Figure 1. This approximately occurs at vertebral level L5-S1.
The artery descends inferiorly, crossing the pelvic inlet to enter the lesser pelvis. During its descent, it is situated medially to the external iliac vein and obturator nerve. At the superior border of the greater sciatic foramen, it divides into anterior and posterior trunks.
The anterior trunk gives rise to numerous branches that supply the pelvic organs, the perineum, and the gluteal and adductor regions of the lower limb. The following branches of the internal iliac artery are highlighted in Figure 2 below, working anti-clockwise from obturator artery to inferior gluteal artery.
The posterior trunk gives rise to arteries that supply the lower posterior abdominal wall, posterior pelvic wall and the gluteal region. There are typically three branches-
An understanding of the anatomy of the pelvic arteries is important for many clinical scenarios. For example, the lumbar and iliac branches of the iliolumbar artery may become blocked leading to a decreased blood supply to the lower lumbar vertebrae or the iliac fossa respectively, resulting in pain and discomfort. In addition, knowledge of the anatomy of the pelvic arteries is essential for surgeons undertaking operations such as hysterectomies, as the uterine artery must be identified and divided to reduce intra-operative bleeding. An understanding of the blood supply of the perineum is also important for surgical procedures such as male or female genital reconstruction.
In summary, the anatomy of the pelvic arteries is complex, yet extremely important for many clinical scenarios. Knowledge of their branching patterns, position relative to the other structures of the pelvis and their clinical relevance is essential to ensure any operations performed in this region are safe and successful.
The internal iliac artery is a major branch of the abdominal aorta, with several specialized branches of the artery that are responsible for supplying arterial blood to the structures of the pelvic region. These branches are highlighted in the Figure 2 below, and are discussed in the following passage as they progress in a clockwise direction, beginning with the Obturator Artery and ending with the Inferior Gluteal Artery.
The Obturator Artery is the first branch of the internal iliac artery that is discussed in this passage. It travels through the obturator canal of the pelvis accompanied by the obturator nerve and vein. It is responsible for supplying blood to the muscles of the adductor region of the thigh.
Following the Obturator Artery in a counter-clockwise direction are the Lateral Sacral Arteries (Superior and Inferior). These arteries travel in an infero-medial direction along the posterior pelvic wall in order to supply blood to the sacral canal, as well as the skin and muscles that are located posterior of the sacrum.
The Superior Gluteal Artery is the terminal branch of the posterior trunk. This artery exits the pelvic cavity and enters the gluteal region via the greater sciatic foramen, superiorly to the piriformis muscle. It is the major blood supply vessel to the muscles and skin of the gluteal region.
In addition to the larger branches of the internal iliac artery discussed above, there are several smaller arteries within the pelvic region that serve vital anatomical and physiological functions. These include the Gonadal Arteries, Median Sacral Artery, Superior Rectal Artery, and the Internal Pudendal Artery.
The Gonadal Arteries are responsible for supplying blood to the gonads. In the case of females, the ovarian artery is the major vessel that arises from the abdominal aorta, distal to the origin of the renal arteries. It descends towards the pelvis, crossing the pelvic brim and the origin of the external iliac vessels. It then moves medially, dividing into an ovarian branch and tubal branches, which supply their respective structures. Note that the testicular artery does not actually enter the pelvis as it reaches the scrotum via the inguinal canal.
The Median Sacral Artery originates from the posterior aspect of the abdominal aorta, at the bifurcation of the common iliac arteries. It descends anteriorly to the L4 and L5 vertebrae, the sacrum,and the coccyx, contributing to the arterial supply of these regions.
The Superior Rectal Artery is the terminal continuation of the inferior mesenteric artery. It crosses the left common iliac artery, descending in the mesentery of the sigmoid colon, and giving rise to branches that supply the rectum.
The Internal Pudendal Artery moves inferiorly to exit the pelvis via the greater sciatic foramen. It is accompanied by the pudendal nerve, which then enters the perineum via the lesser sciatic foramen. The Internal Pudendal Artery is the main vessel responsible for supplying arterial blood to the perineum.
Two other minor arteries of the pelvis are the Umbilical Artery and Inferior Vesical Artery. The Umbilical Artery gives rise to the Superior Vesical Artery, which supplies blood to the superior aspect of the urinary bladder. The Inferior Vesical Artery, on the other hand, supplies the lower aspect of the bladder. In males, it is additionally responsible for supplying the prostate gland and seminal vesicles.
The Vaginal Artery is present in females and descends to the vagina, supplying additional branches to the inferior bladder and rectum. The Uterine Artery, shown below in Figure 3, is another chief artery that is found within the female pelvis. It travels within the cardinal ligament to reach the cervix, ascending along the lateral aspect of the uterus, where it anastomoses with the ovarian artery. During its course, it crosses the ureters superiorly.
The Middle Rectal Artery is responsible for supplying the distal part of the rectum, travelling medially to form anastomoses with the superior rectal artery (derived from the inferior mesenteric) and the inferior rectal artery (derived from the internal pudendal).
The Inferior Gluteal Artery is the terminal branch of the anterior trunk, which leaves the pelvic cavity via the greater sciatic foramen and emerges inferiorly to the piriformis muscle in the gluteal region. It is responsible for contributing to the blood supply of the gluteal muscles and hip joint.
The Iliolumbar Artery ascends to exit the lesser pelvis, dividing into a lumbar and iliac branch. The lumbar branch supplies psoas major, quadratus lumborum, and the posterior abdominal wall.
A hysterectomy is the surgical removal of the uterus and is usually done for a number of indications such as heavy menstrual bleeding, pelvic pain, uterine prolapse (vaginal hysterectomy), and gynaecological malignancy (typically involving the ovaries, uterus and cervix), or as risk-reducing surgery in cases of BRCA 1 or 2 mutations, or Lynch syndrome.
When carrying out a hysterectomy, a comprehensive understanding of the regional anatomy of the pelvis is essential to prevent any damage to surrounding structures while clamping the uterine arteries. The uterine artery, in particular, crosses over the ureters approximately 1 cm laterally to the internal os of the cervix, and the relationship between the two can be easily remembered with the phrase ‘water under the bridge’ - ‘water’ in this instance refers to the ureter (which carries urine), and the uterine artery acting as the ‘bridge’.
When performing a hysterectomy, a good knowledge of regional anatomy is needed to prevent accidentally damaging other structures in the pelvic region. The iliac branch of the abdominal aorta supplies the muscles and bone around the iliac fossa, while the lateral sacral arteries (superior and inferior) travel infero-medially along the posterior pelvic wall to supply structures in the sacral canal, and the skin and muscle posterior to the sacrum. The superior gluteal artery, the terminal branch of the posterior trunk, exits the pelvic cavity via the greater sciatic foramen, entering the gluteal region superiorly to the piriformis muscle; it is the major blood supply to the muscles and skin of the gluteal region.
The ovarian artery is the major gonadal artery in females, arising from the abdominal aorta, distal to the origin of the renal arteries. It descends towards the pelvis, crossing the pelvic brim and the origin of the external iliac vessels before moving medially, dividing into an ovarian branch and tubal branches, which supply their respective structures. The median sacral artery originates from the posterior aspect of abdominal aorta, at its bifurcation into the common iliac arteries. It descends anteriorly, contributing to the arterial supply of the L4 and L5 vertebrae, the sacrum and the coccyx. The superior rectal artery is the terminal continuation of the inferior mesenteric artery; it crosses the left common iliac artery and descends in the mesentery of the sigmoid colon, giving rise to branches that supply the rectum.
The uterine artery crosses the ureters approximately 1 cm laterally to the internal os of the cervix; care must be taken not to damage the ureters during clamping of the uterine arteries during a hysterectomy. The relationship between the two can be remembered using the phrase ‘water under the bridge’, where the water refers to the ureter and the uterine artery is the bridge.
The anatomy of the pelvis is very important to comprehend, as any damage to the vessels, vertebrae, or other structures within the region can cause serious complications. Much of the arterial flow in the pelvis stems from the iliac branch of the abdominal aorta, while the lateral sacral arteries provide blood to the sacral canal and skin and muscle posterior to the sacrum. The superior gluteal artery exits the pelvic cavity via the greater sciatic foramen and is the major blood supply to the muscles and skin of the gluteal region. The ovarian artery is a major gonadal artery in female anatomy, arising from the abdominal aorta and dividing into an ovarian branch and tubal branches which supply their respective structures. The median sacral artery originates from the posterior aspect of abdominal aorta, while the superior rectal artery is the terminal continuation of the inferior mesenteric artery, crossing the left common iliac artery and descends in the mesentery of the sigmoid colon.
When performing a hysterectomy, particular attention must be paid to the uterine artery crossing the ureters approximately 1 cm laterally to the internal os of the cervix; additional care must be taken not to damage the ureters during clamping of the uterine arteries during a hysterectomy. The relationship between the two can be remembered using the phrase ‘water under the bridge’ which serves as a mental reminder to the physician or practitioner of the surrounding anatomy.
As a whole, the anatomy of the pelvis is a complex network of vessels and organs which requires a good understanding of their relationship to each other to ensure a successful procedure is achieved. Any damage or lack of knowledge of the surrounding anatomy can result in serious medical complications.
