Human Anatomy, Part 2 - K. A. Dyubenko, A. K. Kolomiyytsev, Yu. B. Chaykovsky 2008

Special Part
Cardiovascular system, systema cardiovasculare - Special Part
Blood vessels of the systemic circulation - Common iliac artery

The distal end of the Abdominal Aorta bifurcates at the level of the fourth lumbar vertebra into two terminal branches: the common iliac Arteries, aa. iliacae communes (Fig. 42). Except for the aorta itself, these are the largest vessels in The Human Body. The common iliac artery, a. iliaca communis, runs along the medial border of the psoas major Muscle (m. psoas major). At the level of the sacroiliac articulation, each divides into the internal iliac artery, a. iliaca interna, which supplies the walls and Organs of the lesser pelvis, and the external iliac artery, a. iliaca externa, which supplies the lower limb. The common iliac arteries lie within the retroperitoneal space, anterior and to the left of the common iliac Veins. Distally, the Ureter crosses anterior to the common iliac arteries, a crucial consideration in clinical surgical practice. Running vertically downward into the lesser pelvis, the superior rectal artery (a. rectalis superior) lies anterior to the left common iliac artery. The common iliac artery also sends branches to the psoas Major and minor Muscles, the ureter, Lymph Nodes, and surrounding Connective Tissue.

The internal iliac artery, a. iliaca interna (Figs. 46, 47, 47A), is 2–5 cm long and descends alongside its accompanying vein along the lateral wall of the lesser pelvis. Near the upper margin of the greater sciatic foramen, it divides into parietal and visceral branches.

Parietal branches of the internal iliac artery:

1. A. iliolumbalis;

2. A. sacralis lateralis;

3. A. glutea superior;

4. A. obturatoria;

5. A. glutea inferior.

1. The iliolumbar artery, a. iliolumbalis, arises from the internal iliac artery or the superior gluteal artery. It passes posterior to the obturator nerve (n. obturatorius) and the common iliac vein (v. iliaca communis), and near the medial border of the psoas major muscle divides into a lumbar and an iliac branch. The lumbar branch supplies the lumbar muscles, Vertebral Column, and Spinal Cord, while the iliac branch supplies the ilium and the iliacus muscle. It anastomoses with the deep circumflex iliac artery (a. circumflexa ilium profunda) and the fourth lumbar artery (a. lumbalis IV).

2. The lateral sacral artery, a. sacralis lateralis*, originates from the posterior surface of the internal iliac artery near the third medial sacral foramen, and then courses along the pelvic surface of the sacrum medial to the anterior sacral foramina. The lateral sacral artery supplies the piriformis and obturator internus muscles, the Meninges, and the nerve trunks of the Sacral Plexus. It anastomoses with the contralateral lateral sacral artery.

3. The superior gluteal artery, a. glutea superior (Fig. 46), is the largest branch of the internal iliac artery. It exits the pelvis into the gluteal region through the suprapiriform foramen, where it divides into superficial and deep branches. The superficial branch supplies the gluteus maximus and medius muscles, whereas the deep branch supplies the gluteus medius and minimus muscles and the capsule of the hip joint. The superior gluteal artery anastomoses with the inferior gluteal, obturator, and Branches of the deep femoral artery.

4. The obturator artery, a. obturatoria (Fig. 46), predominantly originates from the initial segment of the internal iliac artery, or occasionally from the inferior gluteal artery (3.2%) or the inferior hypogastric artery (2.9%) (according to S. N. Yashchinsky). Together with its accompanying vein and nerve, the obturator artery passes through the obturator canal to reach the medial compartment of the thigh between the pectineus and obturator internus muscles. The origin and course of the obturator artery are of great clinical significance. In 30% of cases, it originates from the inferior epigastric artery (a. epigastrica inferior), and sometimes even from the femoral artery (M. A. Tikhomirov, 1900). When it arises abnormally from the inferior epigastric artery, the obturator artery loops around the femoral canal superiorly, medially, or inferiorly. Concurrently, the femoral vein lies just lateral to the femoral canal. This precarious anatomical relationship is known as the "crown of mortality" or *corona mortis* (P. I. Tikhov, 1914).

* Occasionally, two lateral sacral arteries are present: a superior and an inferior.

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Fig. 46. Arteries of the pelvic cavity in a sagittal section.

Common iliac artery, a. iliaca communis.

External iliac artery, a. iliaca externa.

Internal iliac artery, a. iliaca interna

Near the entrance to the obturator canal, it gives off the pubic branch (r. pubicus*). After emerging from the obturator canal, the artery trifurcates into: 1) An internal branch, supplying the obturator internus muscle; 2) An anterior branch, supplying the obturator externus muscle and the Skin of the external genitalia; and 3) A posterior branch, which runs between the obturator membrane and the external obturator muscle. The latter supplies the articular capsule, the ischium, and the obturator externus muscle, and also sends an acetabular branch (r. acetabularis) through the acetabular notch (incisura acetabuli) into the hip joint cavity, where it reaches and supplies the HEAD of the Femur via the ligament of the head of the femur (lig. capitis femoris). The obturator artery anastomoses with the inferior epigastric, inferior gluteal, and medial femoral circumflex arteries.

* Near the medial margin of the femoral ring, the pubic branch anastomoses with the obturator branch of the inferior epigastric artery (r. obturatorius a. epigastricae inferioris). This anastomosis must be kept in mind during femoral hernia repair.

5. The inferior gluteal artery, a. glutea inferior (Fig. 46), leaves the pelvic cavity through the infrapiriform foramen alongside the internal pudendal artery and the sciatic nerve. It supplies the gluteus maximus muscle, the hip joint, and the skin of the gluteal region, and gives off the artery accompanying the sciatic nerve (a. comitans n. ishiadici). Branches of the inferior gluteal artery anastomose with branches of the superior gluteal and obturator arteries, as well as branches of the lateral femoral circumflex artery (a branch of the deep artery of the thigh).

Visceral Branches of the internal iliac artery (Figs. 47, 47A):

1. A. umbilicalis;

2. A. vesicalis inferior;

3. A. uterina;

4. A.rectalis media;

5. A.pudenda interna.

1. The umbilical artery, a.umbilicalis, is the main branch of the internal iliac artery in the fetus. It runs beneath the parietal Peritoneum along the lateral sides of the Urinary Bladder and reaches the Placenta through the umbilical cord via the umbilical ring. Following birth and ligation of the umbilical cord, the lumen of the a.umbilicalis becomes obliterated over a certain distance, transforming into the medial umbilical ligament, lig.umbilicale mediale. In adults, branches arise from the initial segment of the a.umbilicalis toward the apex of the urinary bladder, namely the superior vesical arteries, aa.vesicales superiores, branches to the lower section of the ureter, rr.ureterici, and the artery of the Ductus deferens in males, a.ductus deferens.

2. The inferior vesical artery, a.vesicalis inferior, originates from the a.iliaca interna, courses forward and downward, reaches the Cytology/practical/108.html">Fundus of the urinary bladder, and supplies Blood to the bladder, Prostate Gland, Seminal Vesicles, and Vagina (in females). Branches of the inferior vesical artery anastomose with branches of the superior vesical artery.

3. The uterine artery, a.uterina (Fig. 48), is present exclusively in females. It originates from the a.iliaca interna*, courses anteriorly along the lateral pelvic wall, then changes direction to a horizontal course and enters the Base of the broad ligament of the Uterus. Anatomical variations exist where the uterine artery may be doubled (Haller) or tripled (Weber). The uterine artery passes between the leaves of the broad ligament, approaches the cervix, and gives off a branch to the vagina, a.vaginalis, while continuing to ascend along the lateral wall of the uterus. The uterine artery supplies branches to the cervix and body of the uterus, the Uterine tube (r.tubarius), and the Ovary (r.ovarius). On its way to the uterus, it crosses the ureter twice: first near its origin, close to the sacroiliac joint, and the second time within the broad ligament of the uterus, about 2 cm short of the uterine cervix—a critical detail that must be considered in clinical surgical practice. The uterine artery anastomoses with the a.ovarica.

* The Water/144.html">Origin of the uterine artery is highly variable. It may arise from the iliolumbar, obturator, superior gluteal, or inferior gluteal artery. Its ligation must be performed lateral to the ureter to avoid compromising another vessel (a.vesicalis superior).

Fig. 47. Visceral and parietal branches of the left internal iliac artery (after Toldt)

4. The middle rectal artery, a.rectalis media, originates from the a.iliaca interna, runs forward along the pelvic floor to reach the lateral wall of the rectal ampulla, and supplies blood to the rectum, the levator ani muscle (m.levator ani), the external anal sphincter, the prostate gland, the seminal vesicles, and—in females—the vagina and Urethra. The middle rectal artery anastomoses with the superior and inferior rectal arteries as well as with the a.pudenda interna.

5. The internal pudendal artery, a.pudenda interna (Fig. 49), is a terminal branch of the a.iliaca interna. It exits the lesser pelvis into the gluteal region through the infrapiriform foramen (foramen infrapiriformis), hooks around the ischial spine (spina ischiadica), and enters the ischioanal fossa via the lesser sciatic foramen (foramen ischiadicum minus), where it runs within the pudendal canal (Alcock's canal, canalis pudendalis) adjacent to the obturator internus muscle and gives off the inferior rectal artery, a.rectalis inferior.

Fig. 47 A. Arteries of the pelvic cavity organs.

Internal iliac artery (left), a.iliaca interna (sinistra), and its branches

The internal pudendal artery gives off several branches:

- The perineal artery, a.perinealis, which supplies the Muscles of the Perineum, Scrotum, or Labia Majora.

- The artery of the bulb of the Penis, a.bulbi penis.

- The deep artery of the penis, a.profunda penis, which supplies the corpus cavernosum.

- The dorsal artery of the penis, a.dorsalis penis, which runs beneath the skin of the penis, supplying the skin, glans penis, and scrotum.

- The urethral artery, a.urethralis, which supplies the urethra.

- The artery of the bulb of the vestibule [vagina], a.bulbi vestibuli [vaginae].

- The deep and dorsal arteries of the Clitoris, aa.profunda et dorsalis clitoridis.

Thus, the a.iliaca interna supplies the hip bone, sacrum, pelvic muscles, internal pelvic organs (rectum, urinary bladder, seminal vesicles, ductus deferens, prostate gland, uterus, and vagina), as well as the external genitalia and perineum.

Fig. 48. Uterine artery, a.uterina (after Toldt)

Fig. 49. Internal pudendal artery, a. pudenda interna, and its branches (after Toldt)