The thoracic aorta begins where the aortic arch ends at the fourth thoracic vertebrae and extends down to the diaphragm. It supplies blood to the thoracic cavity and has several important branches including the bronchial arteries which supply the lungs, esophageal arteries which supply the esophagus, and posterior intercostal arteries which supply the spaces between the ribs. The thoracic aorta also gives off mediastinal and pericardial branches before passing through the diaphragm and becoming the abdominal aorta.

1. Thoracic
aorta
By dr.aisha sadaf
Student
m.phil anatomy

2. 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

4. 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

5. 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

6. 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.

7. 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.

8. 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 azygos
vein; on the right side,
with the hemiazygos
veins and thoracic duct;
on the left side, with the
left pleura and lung.
 Thoracic aorta

9.  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

11. Branches of thoracic aorta

14. (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.

15.  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.

16. 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.

17. Mediastinal branches
 The mediastinal branches are numerous
small vessels which supply the lymph
glands and loose areolar tissue in the
posterior mediastinum.

18. Branches of thoracic aorta

19. 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

20. 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.

22. 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.

23. The end