Thoracic

aorta

By dr.aisha sadaf

Student

m.phil anatomy

Aorta

The aorta is the main arterial trunk that

delivers oxygenated blood from the left

ventricle of the heart to the tissues of the

body. It is divided for purposes of

description into the following parts:

ascending aorta, arch of the aorta,

descending thoracic aorta, and

abdominal aorta

Ascending Aorta

The ascending aorta

begins at the base of

the left ventricle

runs upward and

forward at the level

of the sternal angle,

where it becomes

continuous with the

arch of the aorta

it possesses three bulges, the sinuses of the aorta

Branches The right coronary

artery arises from the anterior aortic sinus, and the left coronary artery arises from the left posterior aortic sinus

Branches of arch of aorta

1. brachiocephalic artery, it divides into the

right subclavian and right common

carotid arteries behind the right

sternoclavicular joint.

2. left common carotid artery

3. left subclavian artery

Thoracic aorta

The thoracic aorta is contained in the

posterior mediastinal cavity.

It begins at the lower border of the fourth

thoracic vertebra where it is continuous

with the aortic arch, and ends in front of

the lower border of the twelfth thoracic

vertebra, at the aortic hiatus in the

diaphragm where it becomes the

abdominal aorta.

Continu….

At its commencement, it is situated on the left of the vertebral column; it approaches the median line as it descends; and, at its termination, lies directly in front of the column.

Relations

It is in relation, anteriorly, from above downward, with the root of the left lung, the pericardium, the esophagus, and the diaphragm; posteriorly, with the vertebral column and the azygosvein; on the right side, with the hemiazygosveins and thoracic duct; on the left side, with the left pleura and lung.

Thoracic aorta

The aorta then arches back over the right

pulmonary artery. Three vessels come out

of the aortic arch: the brachiocephalic

artery, the left common carotid artery,

and the left subclavian artery. These

vessels supply blood to the head, neck,

thorax and upper limbs

Branches of thoracic aorta

(1) VISCERAL BRANCHES

Bronchial-oesophageal artery:

Origin:

arises at the sixth thoracic vertebra from aorta-it descends over the right face of the aorta towards bifurcation of trachea and divided into bronchial anaoesophagial branches.

Bronchial Artery:

It crosses the left face of oesophagous to the bifurcation of trachea where it divides into right and left branches.Each enter into hilus of corresponding lung.

Oesophageal Artery:

The esophageal arteries four or five in number, arise from the front of the aorta, and pass obliquely downward to the esophagus, forming a chain of anastomoses along that tube, anastomosing with the esophageal branches of the inferior thyroid arteries above, and with ascending branches from the left inferior phrenic and left gastric arteries below. These arteries supply the middle third of the esophagus.

Pericardial branches

small branches of thoracic aorta

distributed to the pericardium, in the

region of the oblique pericardial sinus,

and to posterior mediastinal lymph nodes.

Mediastinal branches

The mediastinal branches are numerous

small vessels which supply the lymph

glands and loose areolar tissue in the

posterior mediastinum.

Branches of thoracic aorta

PARIETAL BRANCHES

Superior phrenic artries:

The superior phrenic arteries are small and

arise from the lower part of the thoracic

aorta; they are distributed to the posterior

part of the upper surface of the

diaphragm, and anastomose with the

musculophrenic and pericardiacophrenic

Posterior intercostal arteries The posterior intercostal arteries are arteries

that supply blood to the intercostal spaces.

There are eleven posterior intercostal arteries on each side.

The 1st and 2nd posterior intercostal arteries arise from the supreme intercostal artery, a branch of the costocervical trunk of the subclavian artery.

The lower nine arteries are the aortic intercostals, so called because they arise from the back of the thoracic aorta.

Subcostal branches

The subcostal arteries, so named because they lie below the last ribs, constitute the lowest pair of branches derived from the thoracic aorta, and are in series with the intercostal arteries.

Each passes along the lower border of the twelfth rib behind the kidney and in front of the Quadratus lumborum muscle, and is accompanied by the twelfth thoracic nerve.

The end