The abdominal part of the aorta

From the abdominal part of the aorta, parietal branches extend to the walls of the body and visceral branches supply blood to the internal organs located in the abdominal cavity and, partially, in the pelvic cavity.

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Parietal (wall) branches of the abdominal aorta

1. The inferior phrenic artery (a. phrenica inferior) is the first branch of the abdominal aorta, paired, departing from it in the aortic opening of the diaphragm at the level of or above the celiac trunk. On the way to the diaphragm, the artery gives off from 1 to 24 superior suprarenal arteries (aa. suprarenales superiores), directed downwards to the adrenal gland.
2. The lumbar arteries (aa. lumbales, 4 pairs) branch off from the posterior semicircle of the aorta and go to the abdominal muscles, located between the transverse and internal oblique abdominal muscles. Each lumbar artery gives off a dorsal branch (r. dorsalis) to the muscles and skin of the back in the lumbar region. From the dorsal branch, the spinal branch (r. spinalis) branches off, penetrating through the intervertebral foramen to the spinal cord and its membranes.

Visceral branches of the abdominal aorta

There are unpaired and paired branches. The unpaired branches include the celiac trunk, the superior and inferior mesenteric arteries. The paired branches of the abdominal aorta include the middle adrenal, renal, and testicular (ovarian) arteries.

Unpaired visceral branches of the abdominal aorta

The celiac trunk (truncus coeliacus) is a short vessel 1.5-2.0 cm long, originating from the anterior semicircle of the aorta at the level of the 12th thoracic vertebra. Above the upper edge of the body of the pancreas, the celiac trunk divides into three arteries: the left gastric, common hepatic, and splenic:

1. the left gastric artery (a. gastrica sinistra) runs upward and to the left, towards the cardiac part of the stomach. The artery then runs along the lesser curvature of the stomach (between the layers of the lesser omentum), where it anastomoses with the right gastric artery. The left gastric artery gives off esophageal branches (rr. oesophageales) to the abdominal part of the esophagus. The branches extending from the left gastric artery on the lesser curvature of the stomach run along the anterior and posterior surfaces of the organ and anastomose with the branches of the arteries running along the greater curvature;
2. The common hepatic artery (a. hepatica communis) runs from the celiac trunk to the right and divides into two arteries: the hepatic artery proper and the gastroduodenal artery.
   • The proper hepatic artery (a. hepatica propria) follows the thickness of the hepatoduodenal ligament to the liver and at its gate gives off right and left branches (rr. dexter et sinister). From the right branch, the gallbladder artery (a. cystica) branches off, heading to the gallbladder. From the proper hepatic artery, the thin right gastric artery (a. gastrica dextra) branches off, which anastomoses with the left gastric artery on the lesser curvature of the stomach.
   • The gastroduodenal artery (a. gastroduodenalis) passes behind the pylorus of the stomach and divides into the right gastroepiploic and superior pancreaticoduodenal arteries.
     • The right gastroepiploic artery (a. gastroomentalis, s. gastroepiploica dextra) goes to the left along the greater curvature of the stomach, anastomoses with the left artery of the same name, giving off numerous branches to the stomach and the greater omentum - the omental branches (rr. omentales, s. epiploici).
     • The superior posterior and anterior pancreaticoduodenal arteries (aa. pancreaticoduodenals superiores anterior et posterior) give off branches to the duodenum - duodenal branches (rr. duodenales) and to the pancreas - pancreatic branches (rr. pancreatici);
   • The splenic artery (a. splenica, s. lienalis) is the largest of the branches of the celiac trunk. Along the upper edge of the body of the pancreas, it goes to the spleen, giving off short gastric arteries (aa. gastricae breves) to the bottom of the stomach and branches to the pancreas - pancreatic branches (rr. pancreatici). Having entered the hilus of the spleen, the splenic artery branches into vessels of smaller diameter. At the hilus of the spleen, the left gastroepiploic artery (a. gastroomentalis sa gastroepiploica sinistra) branches off from the splenic artery, which goes along the greater curvature of the stomach to the right. Along its path, the left gastroepiploic artery gives off branches to the stomach - gastric branches (rr. gastrici) and to the omentum - omental branches (rr. omentales). The terminal section of the left gastroepiploic artery at the greater curvature of the stomach anastomoses with the right gastroepiploic artery.

The superior mesenteric artery (a. mesenterica superior) originates from the abdominal part of the aorta behind the body of the pancreas at the level of the 12th thoracic - 1st lumbar vertebra. Following downwards between the head of the pancreas and the lower part of the duodenum, this artery enters the root of the mesentery of the small intestine, where it gives off the following branches:

1. the inferior pancreaticoduodenal artery (a. pancreaticoduodenalis inferioris) departs from the superior mesenteric artery 2 cm below its beginning and goes to the head of the pancreas and to the duodenum, where it anastomoses with the superior pancreaticoduodenal arteries (branches of the gastroduodenal artery);
2. jejunal arteries (aa. jejunales) and
3. ileal arteries (aa.ileales) in the amount of 12-18 depart from the left semicircle of the superior mesenteric artery. They are directed to the loops of the mesenteric part of the small intestine, forming in the mesentery, on the way to the intestinal wall, arc-shaped anastomoses convex towards the intestine - arcades, providing a constant flow of blood to the intestine during its peristalsis;
4. the ileocolic artery (a. ileocolica) runs downward and to the right to the terminal ileum, to the cecum and to the appendix. Along its path, it gives off ileocolic branches (rr. ileales), the anterior and posterior cecal arteries (aa. caecales anterior et posterior), as well as the artery of the vermiform appendix (a. appendicularis) and colic branches (rr. colici) to the ascending colon;
5. the right colic artery (a. colica dextra) begins slightly higher than the previous one (sometimes branches off from it), goes to the right to the ascending colon, anastomoses in the wall of this intestine with the colic branch of the ileocolic artery and with the branches of the middle colic artery;
6. The middle colic artery (a. colica media) branches off from the superior mesenteric artery above the beginning of the right colic artery, runs upward to the transverse colon, and supplies the latter and the upper part of the ascending colon. The right branch of the middle colic artery anastomoses with the right colic artery, and the left forms an anastomosis along the colon (Riolan's arch) with the branches of the left colic artery (from the inferior mesenteric artery).

The inferior mesenteric artery (a. mesenterica inferior) begins from the left semicircle of the abdominal aorta at the level of the third lumbar vertebra, runs behind the peritoneum downwards and to the left and gives off a number of branches to the sigmoid, descending colon and left part of the transverse colon. A number of branches depart from the inferior mesenteric artery:

1. the left colic artery (a. colica sinistra) passes in front of the left ureter and the left testicular (ovarian) artery, divides into descending and ascending branches, supplies the descending colon and the left part of the transverse colon. This artery anastomoses with a branch of the middle colic artery, forming a long anastomosis (Riolan's arch) along the edge of the large intestine;
2. sigmoid colon arteries (aa. sigmoideae, 2-3 in total) are directed to the sigmoid colon, first retroperitoneally, and then in the thickness of the mesentery of this intestine;
3. superior rectal artery (a. rectalis superior) - the terminal branch of the inferior mesenteric artery, directed downwards and divided into two branches. One of them anastomoses with a branch of the sigmoid artery and supplies blood to the lower sections of the sigmoid colon. The other branch descends into the cavity of the small pelvis (in front of the left common iliac artery), branches in the walls of the ampulla of the rectum, anastomosing with the branches of the middle rectal arteries, branches of the internal iliac arteries.

Paired visceral branches of the abdominal aorta:

1. The middle suprarenal artery (a. suprarenalis media) branches off from the aorta at the level of the first lumbar vertebra, slightly below the beginning of the superior mesenteric artery, and goes to the gate of the adrenal gland. On its way, the artery anastomoses with the superior adrenal arteries (from the inferior phrenic artery) and with the inferior adrenal artery (from the renal artery).
2. The renal artery (a. renalis) branches off from the aorta at the level of the I-II lumbar vertebrae, 1-2 cm below the beginning of the superior mesenteric artery, and is directed laterally to the renal hilum. The right renal artery is somewhat longer than the left artery; it passes behind the inferior vena cava. Along its path, the renal artery gives off the inferior suprarenal artery (a. suprarenalis inferior) and ureteric branches (rr. ureterici) to the ureter. In the renal parenchyma, the renal artery branches according to the internal structure of the kidney.
3. The testicular (ovarian) artery (a. testicularis, a. ovarica) is a thin, long vessel that branches off from the aorta at an acute angle below the renal artery. Sometimes the right and left arteries branch off from the aorta in a common trunk. The testicular artery passes through the inguinal canal as part of the spermatic cord to the testicle, and the ovarian artery reaches the ovary in the thickness of the ligament suspending the ovary. The testicular artery gives off ureteral branches (rr. ureterici) and branches of the epididymis (rr. epididymites), anastomoses with the cremasteric artery (from the inferior epigastric artery) and with the artery of the vas deferens (from the umbilical artery). The ovarian artery also gives off ureteral branches (rr. ureterici) and tubal branches (rr. tubarii), anastomoses with the ovarian branch of the uterine artery.

At the level of the middle of the IV lumbar vertebra, the abdominal part of the aorta divides into two common iliac arteries, forming the bifurcation of the aorta (bifurcatio aortae), and itself continues into a thin vessel - the median sacral artery (a. sacralis mediana), which goes down the pelvic surface of the sacrum into the small pelvis.

The branches of the abdominal aorta are connected by numerous anastomoses both among themselves and with the branches of the thoracic aorta and the branches of the iliac arteries.