Learn something new every day More Info... by email
The aorta is the largest artery in the body and has a primary purpose of carrying blood from the heart to other parts of the body. It's shaped somewhat like a candy cane. The short side of the "candy cane" is called the ascending aorta. The long side of the "candy cane" is known as the descending aorta. The curved part of the "candy cane" — the part that connects the long side (descending aorta) and short side (ascending aorta) together — is called the aortic arch. The descending aorta itself is divided into two parts, based on their locations in the body — the thoracic aorta and the abdominal aorta.
The thoracic aorta begins at the bottom of the fourth thoracic vertebra (T4). It continues down to T12 and ends in the diaphragm. There are seven arterial branches that stem from the thoracic aorta. Of these seven, four belong to the visceral branch group and three are parietal branches.
The visceral branches include the pericardial, bronchial, esophageal and mediastinal arterial branches. The visceral branches supply oxygenated blood to the outer walls of the heart, the lungs, the esophogus the thymus gland and the lymph nodes.
The parietal branches include the intercostal, subcostal and superior phrenic branches. These supply blood to the intercostal muscles between the ribs, the abdominal muscles and the diaphragm.
The abdominal descending aorta continues where the thoracic aorta leaves off. It starts at the T12 vertebra of the thoracic spine and ends at L4 — the fourth vertebra in the lumbar spine. The end of the abdominal aorta is also the end of the entire aorta. From there, the aorta branches off into two arteries — the left common iliac artery and the right common iliac artery. They travel down each of the legs to supply blood to the lower limbs.
While the thoracic aorta has seven branches, the abdominal aorta has 11. The 11 branches of the abdominal aorta can be divided into three groups — the visceral, parietal and terminal branches. These branches supply oxygenated blood to the organs in the abdomen, pelvis and both legs.
The visceral branches are celiac, superior mesenteric, inferior mesenteric, middle suprarenals and renals. In addition, males also have the internal spermatic branch, while females have a corresponding ovarian branch. The celiac, superior mesenteric and inferior mesenteric arteries and their branches supply oxygenated blood to the stomach, liver, gall bladder, spleen, pancreas, the intestines and the appendix. The middle suprarenal and renal arteries supply blood to the kidneys and excretory organs. The spermatic arteries and ovarian arteries supply oxygenated blood to the corresponding reproductive organs, namely, the testes and vas deferens in males and the ovaries in females.
The parietal branches are the inferior phrenics, lumbars and middle sacral. Of the parietal branches, the inferior phrenic arteries supply blood to the diaphragm. The lumbar arteries supply blood to most of the abdominal muscles. The middle sacral branches supply blood to the sacrum and coccyx area and the rectum. It also connects with the iliac vein.
Finally, the terminal branches are called the common iliacs. The common iliac artery branches off to form the external and internal iliac arteries, which supply the legs with oxygenated blood.