Human Anatomy - Kotsan I. Y. 2009

Vessels of the Lesser (Pulmonary) Circulation
Branches of the Abdominal Aorta
Paired Visceral Branches of the Abdominal Aorta

The middle suprarenal artery (a. suprarenalis media) is a slender, paired vessel that originates from the lateral surface of the aorta at the level of the 1st lumbar vertebra and courses transversely toward the hilum of the respective suprarenal gland. Along its path, it anastomoses with the superior suprarenal Arteries (derived from the inferior phrenic artery) and the inferior suprarenal artery (derived from the renal artery).

The renal artery (a. renalis) is a large, paired vessel branching off the lateral surface of the aorta at the level of the 1st–2nd lumbar vertebrae (slightly inferior to the previous artery). During its course, the renal artery gives off the inferior suprarenal artery (a. suprarenalis inferior) to the suprarenal gland, capsular branches (aa. capsulares) to the renal capsule, and ureteric branches (rr. ureterici) to the Ureter. Within the renal parenchyma, the renal artery divides in accordance with the segments and lobes of the Kidney.

The testicular artery (a. testicularis) in males, or the ovarian artery (a. ovarica) in females, consists of paired, slender vessels originating from the anterior surface of the Abdominal Aorta just inferior to the renal arteries. The right testicular (ovarian) artery may occasionally branch from the right renal artery. In males, the testicular artery traverses the Inguinal Canal as a component of the Spermatic Cord to reach the Testis; in females, the ovarian artery travels within the suspensory ligament of the Ovary to reach the organ. The ovarian artery anastomoses with the ovarian branch of the uterine artery. The testicular artery anastomoses with the cremasteric artery (a branch of the inferior epigastric artery) and the artery of the Ductus deferens (a branch of the umbilical artery).

Anastomoses among the visceral Branches of the abdominal aorta. The Visceral Branches of the abdominal aorta are interconnected by numerous anastomoses. Notable Examples include: 1) the anastomosis between the esophageal branches (from the Thoracic Aorta) and the left gastric artery (from the celiac trunk); 2) the left gastric artery and the right gastric artery (a branch of the proper hepatic artery), which anastomose along the lesser curvature of The Stomach, while the right gastroepiploic artery (from the gastroduodenal artery) and the left gastroepiploic artery (a branch of the splenic artery) anastomose along the greater curvature; 3) intrapancreatic anastomoses: the superior pancreaticoduodenal arteries (from the gastroduodenal artery) anastomose with the inferior pancreaticoduodenal arteries (from the superior mesenteric artery); 4) anastomoses within the mesentery of the Small Intestine: jejunal arteries interconnect with one another and with ileal arteries, whereas ileal arteries anastomose among themselves and with the ileocolic artery; 5) anastomoses among the branches of the colic arteries: the ileocolic artery connects with the right and middle colic arteries (all originating from the superior mesenteric artery), and the middle colic artery anastomoses with the left colic artery (from the inferior mesenteric artery); 6) rectal arterial anastomoses: the superior rectal artery (from the inferior mesenteric artery) anastomoses with the middle rectal artery (from the internal iliac artery) and the inferior rectal artery (a branch of the internal pudendal artery).

At the level of the mid-body of the 4th lumbar vertebra, the abdominal aorta bifurcates into the two common iliac arteries, forming the aortic bifurcation (bifurcatio aortica).

The common iliac artery (a. iliaca communis), measuring 1.1–1.25 cm in diameter and 5–6 cm in length, extends inferiorly and laterally from the aortic bifurcation and divides into the internal and external iliac arteries at the level of the sacroiliac joint.

The internal iliac artery (a. iliaca interna) supplies the walls and Organs of the pelvis. Originating from the common iliac artery at the level of the sacroiliac joint, it descends along the medial margin of the psoas major Muscle into the pelvic cavity, and at the level of the upper margin of the greater sciatic foramen, it divides into two main trunks—posterior and anterior—which supply the pelvic walls and viscera. The posterior trunk predominantly gives rise to parietal branches, whereas the anterior trunk gives rise to visceral (organ) branches.

Parietal branches of the internal iliac artery:

1. The iliolumbar artery (a. iliolumbalis) courses posterior to the psoas major muscle laterally toward the iliac fossa, where it divides into lumbar and iliac branches. The lumbar branch (r. lumbalis) supplies the psoas major and quadratus lumborum Muscles. A slender spinal branch (r. spinalis) arises from the lumbar branch, enters the vertebral canal via the intervertebral foramen between the 5th lumbar vertebra and the sacrum, and supplies the Spinal Cord and its Meninges. The iliac branch (r. iliacus) supplies the ilium and the iliacus muscle, anastomosing with the deep circumflex iliac artery (from the external iliac artery).

2. The lateral sacral arteries (aa. sacrales laterales)—superior and inferior—run toward the bones and Muscles of the sacral region; their spinal branches (rr. spinales) pass through the pelvic sacral foramina into the sacral canal to supply the spinal meninges.

3. The superior gluteal artery (a. glutealis superior), the largest branch of the internal iliac artery, exits the pelvis through the suprapiriformis foramen, where it divides into superficial and deep branches. The superficial branch (r. superficialis) runs between the gluteus maximus and gluteus medius muscles, supplying the muscles and Skin of the gluteal region. The deep branch (r. profundus) passes between the gluteus medius and gluteus minimus muscles, further subdividing into superior and inferior branches (rr. superior et inferior) that supply the gluteus medius and minimus, as well as adjacent pelvic muscles. Additionally, the inferior branch contributes to the Blood supply of the hip joint, anastomosing with branches of the lateral femoral circumflex artery (from the deep femoral artery).

4. The obturator artery (a. obturatoria) arises from the anterior trunk of the internal iliac artery, courses along the lateral wall of the lesser pelvis anteriorly toward the obturator foramen, and exits the pelvic cavity via the obturator canal onto the thigh, where it divides into anterior and posterior branches. The anterior branch (r. anterior) supplies the external obturator muscle, the upper adductors of the thigh, and the skin of the external genitalia. The posterior branch (r. posterior) supplies the internal and external obturator muscles and the ischium, giving off an acetabular branch (r. acetabularis) that passes through the acetabular notch and subsequently travels within the ligament of the HEAD of the Femur to supply the femoral head and hip joint. Prior to entering the obturator canal, the obturator artery gives off a pubic branch (r. pubicus) that hooks behind the superior ramus of the pubis to reach the Pubic Symphysis. Near the symphysis, the pubic branch anastomoses with the obturator branch of the inferior epigastric artery, forming a clinically significant anastomosis medial to the femoral ring known as the "corona mortis". It is so named because this arterial anastomosis is frequently well-developed, and Hemorrhage from it can be difficult to control if damaged during the surgical repair of a femoral hernia.

5. The inferior gluteal artery (a. glutealis inferior) originates from the anterior trunk of the internal iliac artery, courses across the anterior surface of the piriformis muscle and the Sacral Plexus, and leaves the pelvic cavity through the infrapiriformis foramen alongside the sciatic nerve and internal pudendal artery. It ramifies within the gluteus maximus muscle and anastomoses with other Arteries of the gluteal region. It gives off the slender artery accompanying the sciatic nerve (a. comitans nervi ischiadici), as well as several branches supplying the hip joint, skin, and muscles of the gluteal region.

Visceral branches of the internal iliac artery:

1. The umbilical artery (a. umbilicalis) is one of the largest branches of the internal iliac artery during the Embryonic period. It arises from the anterior trunk of this artery and courses anteriorly and superiorly along the posterior aspect of the anterior abdominal wall (subperitoneally) toward the umbilicus. In the adult, the greater part of the umbilical artery obliterates, transforming into the medial umbilical ligament. Its initial segment remains patent and functional throughout life. From this patent portion arise the artery of the ductus deferens (a. ductus deferentis in males), which runs alongside the ductus deferens to the testis, supplying it and anastomosing with the testicular artery; ureteric branches (rr. ureterici), which supply the lower segment of the ureter; and superior vesical arteries (aa. vesicales superiores), which head toward and supply the upper portion of the Urinary Bladder.

2. The inferior vesical artery (a. vesicalis inferior) courses inferiorly and anteriorly, supplying the urinary bladder (in conjunction with the superior vesical arteries), the Prostate Gland, and the Seminal Vesicles (in males), as well as partially supplying the Vagina (in females).

3. The uterine artery (a. uterina) originates from the anterior trunk of the internal iliac artery or from the initial part of the umbilical artery, runs medially and inferiorly, crosses the ureter, and reaches the cervix between the layers of the broad ligament of the Uterus. It supplies the uterus and gives off the vaginal artery (a. vaginalis), whose branches anastomose with corresponding branches from the contralateral side, alongside the tubal and ovarian branches (r. tubarius et r. ovaricus). Within the mesovarium, the ovarian branch anastomoses with branches of the ovarian artery (derived from the abdominal aorta).

4. The middle rectal artery (a. rectalis media) is a small, inconstant vessel. It typically arises independently from the anterior trunk of the internal iliac artery, though occasionally it stems from the inferior vesical or internal pudendal arteries. It supplies blood to the rectal ampulla and the levator ani muscle, anastomoses with the superior and inferior rectal arteries, and sends branches to the prostate gland, seminal vesicles (in males), and vagina (in females).

5. The internal pudendal artery (a. pudenda interna) is the terminal branch of the anterior trunk of the internal iliac artery. It exits the pelvis through the infrapiriformis foramen, hooks around the ischial spine, and re-enters the pelvic cavity via the lesser sciatic foramen, where it enters the ischioanal fossa. The internal pudendal artery gives off the following branches: the inferior rectal artery (a. rectalis inferior), which supplies the muscles and mucosa of the anal canal, as well as the surrounding fat and skin; the perineal artery (a. perinealis), which supplies the bulbospongiosus and ischiocavernosus muscles; the urethral artery (a. urethralis), which in males runs alongside the Urethra within the corpus spongiosum of the Penis to the glans and anastomoses with the deep and dorsal penile arteries; the posterior scrotal branches (rr. scrotales posteriores) in males, or posterior labial branches (rr. labiales posteriores) in females, which supply the Scrotum or Labia Majora; the artery of the bulb of the penis / Vestibule of the vagina (a. bulbi penis / vestibuli vaginae); the deep artery of the penis / Clitoris (a. profunda penis / clitoridis); and the dorsal artery of the penis / clitoris (a. dorsalis penis / clitoridis). Functionally acting as a direct continuation of the internal pudendal artery, the dorsal artery of the penis runs distally along the dorsum of the penis between the deep fascia and the tunica albuginea—flanking the median dorsal vein of the penis—alongside its contralateral counterpart.

The external iliac artery (a. iliaca externa) is the direct continuation of the common iliac artery. It courses inferiorly along the medial border of the psoas major muscle, passes beneath the inguinal ligament through the vascular lacuna onto the thigh, where it becomes known as the femoral artery. Along its course, the external iliac artery supplies small branches to the psoas major muscle and gives off two major branches: the inferior epigastric artery and the deep circumflex iliac artery.

1. The inferior epigastric artery (a. epigastrica inferior) originates from the anterior surface of the external iliac artery just before it enters the vascular lacuna, and runs superiorly and medially along the posterior aspect of the anterior abdominal wall between the Peritoneum and the transversalis fascia toward the rectus abdominis muscle. Near its origin, the inferior epigastric artery gives off the pubic branch and the cremasteric artery. The pubic branch (r. pubicus) is a small twig that travels along the posterior surface of the pubic bone to the pubic symphysis, supplying the pyramidalis muscle and the lower portion of the rectus abdominis, while also sending off an obturator branch (r. obturatorius) that anastomoses with the pubic branch of the obturator artery. The cremasteric artery (a. cremasterica) branches off the inferior epigastric artery slightly superior to the pubic branch, traverses the inguinal canal, and supplies the coverings of the spermatic cord and testis, as well as the cremaster muscle in males. In females, the homologous vessel is the artery of the round ligament of the uterus (a. ligamentum teretis uteri), which supplies the round ligament and the labia majora.

2. The deep circumflex iliac artery (a. circumflexa iliaca profunda) arises from the lateral wall of the external iliac artery, courses posteriorly along the iliac crest, supplies branches to the muscles of the anterolateral abdominal wall, and anastomoses with branches of the iliolumbar artery.