Thoracic aorta
Encyclopedia
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
.
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.
The vessel describes a curve which is concave forward; as the branches given off from it are small, its diminution in size is insignificant.
It has a radius of approximately 1.16 cm.
, 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.
The esophagus, with its accompanying plexus of nerves, lies on the right side of the aorta above; but at the lower part of the thorax it is placed in front of the aorta, and, close to the diaphragm, is situated on its left side.
, the ascending aorta
, rises out of the left ventricle, from which it is separated by the aortic valve
. The two coronary arteries of the heart arise from the aortic root, just above the cusps of the aortic valve
.
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 limb
s.
Note: The posterior intercostal arteries are branches that originate throughout the posterior aspect of the thoracic aorta.
It begins at the lower border of the fourth thoracic vertebra where it is continuous with the aortic arch
Aortic arch
The arch of the aorta or the transverse aortic arch is the part of the aorta that begins at the level of the upper border of the second sternocostal articulation of the right side, and runs at first upward, backward, and to the left in front of the trachea; it is then directed backward on the left...
, and ends in front of the lower border of the twelfth thoracic vertebra, at the aortic hiatus
Aortic hiatus
The aortic hiatus is a hole in the human diaphragm. It is the lowest and most posterior of the large apertures.It is located approximately at the level of the twelfth thoracic vertebra .-Structure:...
in the diaphragm where it becomes the abdominal aorta
Abdominal aorta
The abdominal aorta is the largest artery in the abdominal cavity. As part of the aorta, it is a direct continuation of the descending aorta .-Path:...
.
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.
The vessel describes a curve which is concave forward; as the branches given off from it are small, its diminution in size is insignificant.
It has a radius of approximately 1.16 cm.
Relations
It is in relation, anteriorly, from above downward, with the root of the left lungLung
The lung is the essential respiration organ in many air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located near the backbone on either side of the heart...
, the pericardium
Pericardium
The pericardium is a double-walled sac that contains the heart and the roots of the great vessels.-Layers:...
, the esophagus
Esophagus
The esophagus is an organ in vertebrates which consists of a muscular tube through which food passes from the pharynx to the stomach. During swallowing, food passes from the mouth through the pharynx into the esophagus and travels via peristalsis to the stomach...
, and the diaphragm; posteriorly, with the vertebral column
Vertebral column
In human anatomy, the vertebral column is a column usually consisting of 24 articulating vertebrae, and 9 fused vertebrae in the sacrum and the coccyx. It is situated in the dorsal aspect of the torso, separated by intervertebral discs...
and the azygos vein
Azygos vein
The azygos vein is a vein running up the right side of the thoracic vertebral column. It can also provide an alternate path for blood to the right atrium by allowing the blood to flow between the venae cavae when one vena cava is blocked.-Structure:...
; on the right side, with the hemiazygos veins and thoracic duct
Thoracic duct
In human anatomy, the thoracic duct of the lymphatic system is the largest lymphatic vessel in the body. It is also known as the left lymphatic duct, alimentary duct, chyliferous duct, and Van Hoorne's canal....
; on the left side, with the left pleura and lung.
The esophagus, with its accompanying plexus of nerves, lies on the right side of the aorta above; but at the lower part of the thorax it is placed in front of the aorta, and, close to the diaphragm, is situated on its left side.
Branches before thoracic aorta
The initial part of the aortaAorta
The aorta is the largest artery in the body, originating from the left ventricle of the heart and extending down to the abdomen, where it branches off into two smaller arteries...
, the ascending aorta
Ascending aorta
The ascending aorta is a portion of the aorta commencing at the upper part of the base of the left ventricle, on a level with the lower border of the third costal cartilage behind the left half of the sternum; it passes obliquely upward, forward, and to the right, in the direction of the heart’s...
, rises out of the left ventricle, from which it is separated by the aortic valve
Aortic valve
The aortic valve is one of the valves of the heart. It is normally tricuspid , although in 1% of the population it is found to be congenitally bicuspid . It lies between the left ventricle and the aorta....
. The two coronary arteries of the heart arise from the aortic root, just above the cusps of the aortic valve
Aortic valve
The aortic valve is one of the valves of the heart. It is normally tricuspid , although in 1% of the population it is found to be congenitally bicuspid . It lies between the left ventricle and the aorta....
.
The aorta then arches back over the right pulmonary artery
Pulmonary artery
The pulmonary arteries carry deoxygenated blood from the heart to the lungs. They are the only arteries that carry deoxygenated blood....
. Three vessels come out of the aortic arch
Aortic arch
The arch of the aorta or the transverse aortic arch is the part of the aorta that begins at the level of the upper border of the second sternocostal articulation of the right side, and runs at first upward, backward, and to the left in front of the trachea; it is then directed backward on the left...
, the brachiocephalic artery
Brachiocephalic artery
The brachiocephalic artery is an artery of the mediastinum that supplies blood to the right arm and the head and neck....
, the left common carotid artery
Common carotid artery
In human anatomy, the common carotid artery is an artery that supplies the head and neck with oxygenated blood; it divides in the neck to form the external and internal carotid arteries. - Structure :...
, and the left subclavian artery
Subclavian artery
In human anatomy, the subclavian arteries are two major arteries of the upper thorax , below the clavicle . They receive blood from the top of the aorta...
. These vessels supply blood to the head
Head
In anatomy, the head of an animal is the rostral part that usually comprises the brain, eyes, ears, nose and mouth . Some very simple animals may not have a head, but many bilaterally symmetric forms do....
, neck
Neck
The neck is the part of the body, on many terrestrial or secondarily aquatic vertebrates, that distinguishes the head from the torso or trunk. The adjective signifying "of the neck" is cervical .-Boner anatomy: The cervical spine:The cervical portion of the human spine comprises seven boney...
, thorax
Thorax
The thorax is a division of an animal's body that lies between the head and the abdomen.-In tetrapods:...
and upper limb
Upper limb
The upper limb or upper extremity is the region in an animal extending from the deltoid region to the hand, including the arm, axilla and shoulder.-Definition:...
s.
Branches of thoracic aorta
The aorta gives off several paired branches as it descends in the thorax. In descending order, these include the- Bronchial arteries,
- Mediastinal arteries, Mediastinal branches of thoracic part of aortaMediastinal branches of thoracic part of aortaThe mediastinal branches are numerous small vessels which supply the lymph glands and loose areolar tissue in the posterior mediastinum....
- esophageal arteries,
- Pericardial arteries, and the
- Superior phrenic arterySuperior phrenic arteryThe 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 arteries....
Note: The posterior intercostal arteries are branches that originate throughout the posterior aspect of the thoracic aorta.