Arteries of Thorax

Thoracic Artery

The two internal thoracic arteries can be differentiated as left and right. One on the either side of sternum and is located deep towards the anterior chest wall. The initial part of the subclavian artery (lower surface) is the source of the internal thoracic artery situated around 2.5 cm over the medial end of the clavicle, opposite the origin of the thyrocervical trunk.

The internal thoracic artery descends behind the medial end of the clavicle and upper 6 coastal cartilages, about 1 cm far from the lateral margin of the sternum. It finishes in the 6th intercostal space by breaking up into superior epigastric and musculophrenic arteries.

Subclavian Artery

It is found below the clavicle that is why it is called subcalvian artery. It’s the primary source of blood supply to the upper limb and therefore termed artery of the upper limb. On the other hand, the subclavian artery also supplies appreciable part of the thoracic wall, head, neck and brain via its branches.

The point of origin is from the brachiocephalic trunk supporting the right sternoclavicular joint in the root of neck. The left subclavian artery originates from the arch of aorta in the thorax. It runs upwards on the left mediastinal pleura and makes groove on the left lung and enters the neck by passing behind the left sternoclavicular joint.

Pulmonary Artery

The pulmonary arteries emerge via the Truncus Arteriosus and the Sixth Pharyngeal Arch. It divides into two branches Right Pulmonary Artery and Left Pulmonary Artery. The right and left pulmonary arteries supply deoxygenated blood to the lungs via the right ventricle of the heart. The branching of the pulmonary trunk takes place anteroinferiorly towards the left of the branching of the trachea and near the left of the midline just inferior towards T4/T5 vertebral level. The Pulmonary arteries are the only arteries in the body that carry deoxygenated blood.

The right pulmonary artery travels horizontally across the mediastinum and is longer compared to the left branch. It travels:

Anteriorly towards the right main bronchus and anteriorly as well as a little inferiorly to the tracheal branching and,

Posteriorly towards the ascending aorta, superior vena cava, along with upper right pulmonary vein.

Carotid Artery

They can be called the main arteries of the head and neck. There are 2 common carotid arteries: left and right. The right common carotid artery originates behind the sternoclavicular joint, in neck from brachiocephalic trunk (innominate artery).The left common carotid artery originates directly from the arch of aorta in thorax (superior mediastinum). It ascends to the rear of left sternoclavicular joint and enters the neck.

Superior Epigastric Artery

The superior epigastric artery emerges around the sixth or seventh costal cartilage and is a section of internal thoracic artery. While moving across the diaphragm in the space between the costal as well as the sternal parts of the muscle, it declines to the anterior abdominal wall.

The superior epigastric artery by entering the gap between the costal and xiphoid slips at the start of the diaphragm goes inside the rectus and also enters deep to the rectus abdominis. At the same time a section of external iliac artery, the inferior epigastric artery, by coming in front of the arcuate line moves in the sheath. These arteries circulate the rectus muscle and also anastomose along with each other inside the sheath.

Inferior Epigastric Artery

The inferior epigastric artery emerges deep towards the inguinal ligament, via the terminal part of the external iliac artery, often straight via the source of the deep circumflex iliac artery, and also seldom as a common trunk along with the obturator artery. It is often referred to as deep inferior epigastric artery.

At their beginning the inferior epigastric arteries normally possess a standard diameter around 3 mm, probably revealing the reasons why the inferior epigastric arteries give the main supply to rectus abdominis, as compared to a normal diameter about 1.6 mm on the creation of the superior epigastric arteries. Division into two arteries prior to anastomosis is one of the most normal arrangements, making up nearly 60% of scenarios, along with a trifurcation existing in the remainder. In around 30% of situations the inferior epigastric arteries rise and anastomose along with their superior counterpart with no branching.

Subcostal Arteries

The subcostal arteries are the final pair of parietal branches produced by the thoracic aorta. They are located under the last ribs; however, they remain in sequence along with the aortic intercostal arteries. A posterior branch which behaves similarly as the posterior branch produced by an ordinary aortic intercostal artery is produced by each one of them.

Alongside the last thoracic nerve, the trunk goes towards the lower border of the twelfth rib. It goes towards the abdomen under the arcus lumbocostalis lateralis, and then anteriorly towards the quadratus lumborum, and posterior towards the colon and the kidney.

The subcostal artery circulates some muscles within the walls of the thorax along with abdomen. The artery produces a dorsal section the circulation of which resembles that of the equivalent sections of the posterior intercostal arteries.