HealthMedicine

Anatomy of the aorta and its branches

The aorta is the largest vessel in the body, both in length and diameter, and in the volume of blood flow, so the proper blood supply of all organs and systems of the body depends on it. The pathology of this largest in the human body arteries adversely affects the work of all organs, the vessels to which branch off below the level of defeat.

Anatomy of the aorta

Conditionally, this large vessel is divided into three parts, proceeding from its direction:

  • Ascending department.
  • Aortic arch, anatomy of which is considered separately.
  • The downward part. This department is the longest. It ends when approaching the fourth lumbar vertebra. Here the common iliac arteries begin, on which the abdominal aorta divides.

Anatomy and topography

The ascending part of the aorta extends from the left ventricle. Having reached the second rib, it passes into a so-called arc, which, bending to the left, at the level of the fourth vertebra of the thoracic spine turns into the descending part.

Anatomy of the aorta and the location of its parts and main branches relative to other internal organs at different levels is of great importance in studying the structure of the thoracic and abdominal cavities.

Thoracic department

Starting at the level of the fourth thoracic vertebra, the thoracic segment of the aorta is directed almost vertically downwards, located in the region of the posterior mediastinum. To the right of the aorta, there is a thoracic duct and an unpaired vein; On the left - a parietal pleura leaf.

Abdomen

This department begins when the aortic vessel passes through the corresponding aperture in the diaphragm and extends to the level of the fourth lumbar vertebra. In the abdominal cavity the anatomy of the aorta has its own peculiarity: it lies in the retroperitoneal cell space, over the vertebral bodies of the lumbar region, surrounded by the following organs:

  • To the right of it lies the inferior vena cava;
  • From the front side to the ventral aorta adjoin the posterior surface of the pancreas, the horizontal segment of the duodenum, as well as part of the root of the mesentery of the small intestine.

Having reached the level of the fourth vertebra of the lumbar region, the abdominal aorta is divided into two iliac arteries. They provide the blood supply to the lower extremities (this place is called bifurcation, bifurcation of the aorta, and is its end).

In accordance with the arrangement of parts of this large vessel, the anatomy of the aorta and its branches is examined by departments.

Branches of the ascending department

This is the initial section of the vessel. Its duration is not long: from the left ventricle of the heart to the cartilage of the second rib on the right.

At the very beginning of the ascending aorta, the right and left coronary arteries branch out from it , the blood supply area of which is the heart.

Aortic arch branches

The anatomy of the arch has the following peculiarity: from its convex part, large arteries originate, carrying blood supply to the skull and upper limbs. The concave part gives off an insignificant branch size, not having a permanent arrangement.

From the convex side of the arch of the aorta, the following branches extend (from right to left):

  • Brachiocephalic trunk ("brachiocephalic");
  • Left common carotid artery;
  • Left subcllavicular artery.

The concave part of the arc gives thin arterial vessels, suitable for the trachea and bronchi. Their number and location may be different.

Branches of the descending department

The descending aorta, in turn, is divided into divisions:

  1. Thoracic, located above the diaphragm;
  2. Abdominal, located below the diaphragm.

Thoracic department:

  • Parietal arterial vessels for blood supply to the walls of the chest: upper diaphragmatic arteries, branched surfaces of the diaphragm from the thoracic cavity, and posterior intercostal arterial vessels that supply blood to the intercostal and direct abdominal muscles, the mammary gland, the spinal cord, and soft back tissues.
  • The visceral vessels that extend from the thoracic region branch into the organs of the posterior mediastinum.

Abdominal department:

  • Parietal branches branched into the walls of the abdominal cavity (four pairs of lumbar arteries, blood supplying muscles and skin of the lumbar region, abdominal walls, lumbar spine and spinal cord) and the lower surface of the diaphragm.
  • The visceral arterial branches reaching the organs of the abdominal cavity are paired (to the adrenals, kidneys, ovaries and testicles, and the names of arteries correspond to the names of the organs they supply) and unpaired. The names of the visceral arteries correspond to the names of the organs they supply with blood.

The structure of the vessel wall

The concept of "anatomy of the aorta" includes the structure of the wall of this largest in the body of the arterial vessel. The structure of its wall has certain differences from the structure of the wall of all other arteries.

The structure of the aortic wall is as follows:

  • Inner shell (intima). It is a basal membrane lined with endothelium. Endothelium actively reacts to signals received from the blood circulating in the vessel, transforms them and transfers to the smooth muscle layer of the vascular wall.
  • The middle shell. This layer consists of the aorta of circularly arranged elastic fibers (as opposed to other arterial vessels in the body, where both collagen and smooth muscle and elastic fibers are represented - without a vivid predominance of any of them). Anatomy of the aorta has a feature: the middle shell of the aortic wall is formed mainly by elastic fibers. The function of the middle shell is to maintain the shape of the vessel, and also provides its motor. The middle layer of the vascular wall is surrounded by an interstitial substance (liquid), the major part of which penetrates here from the blood plasma.
  • Advent (the outer shell of the vessel). This connective tissue layer contains mainly collagen fibers and perivascular fibroblasts. It is permeated with blood capillaries and contains in large quantities the endings of vegetative nerve fibers. The perivascular connective tissue layer is also a conductor of signals directed towards the vessel, as well as pulses emanating from it.

Functionally, all layers of the vascular wall are interconnected and capable of transmitting the information impulse to each other - from the intima to the middle layer and adventitia, and in the opposite direction.

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