Posterior intercostal arteries
Encyclopedia
The posterior intercostal arteries are arteries that supply blood to the intercostal space
s.
There are eleven posterior intercostal arteries on each side.
The right aortic intercostals are longer than the left because of the position of the aorta on the left side of the vertebral column; they pass across the bodies of the vertebrae behind the esophagus
, thoracic duct
, and azygos vein
, and are covered by the right lung
and pleura.
The left aortic intercostals run backward on the sides of the vertebrae and are covered by the left lung
and pleura; the upper two vessels are crossed by the left superior intercostal vein
, the lower vessels by the hemiazygos vein
.
Opposite the heads of the ribs, the sympathetic trunk
passes downward in front of them, and the splanchnic nerves
also descend in front by the lower arteries.
Each artery then divides into an anterior and a posterior ramus.
A given posterior intercostal artery travels along the bottom of the rib with its corresponding posterior intercostal vein, as well as the intercostal nerve of the given space. The vein is superior to the artery, and the intercostal nerve is inferior to it. Commonly, the mnemonic, "Van," is used to recall the order of the vein, artery and nerve, from superior to inferior.
Intercostal space
The intercostal space is the space between two ribs . Since there are 12 ribs on each side, there are 11 intercostal spaces, each numbered for the rib superior to it.-Structures in intercostal space:* several kinds of intercostal muscle...
s.
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 trunkCostocervical trunkThe costocervical trunk arises from the upper and back part of the subclavian artery, behind the scalenus anterior on the right side, and medial to that muscle on the left side....
of the subclavian arterySubclavian arteryIn 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...
. - The lower nine arteries are the aortic intercostals, so called because they arise from the back of the thoracic aortaThoracic aortaThe 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...
.
The right aortic intercostals are longer than the left because of the position of the aorta on the left side of the vertebral column; they pass across the bodies of the vertebrae behind 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...
, 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....
, and 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:...
, and are covered by the right lung
Lung
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...
and pleura.
The left aortic intercostals run backward on the sides of the vertebrae and are covered by the left lung
Lung
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...
and pleura; the upper two vessels are crossed by the left superior intercostal vein
Superior intercostal vein
The superior intercostal veins are two veins that drain the 2nd, 3rd, and 4th intercostal spaces, one vein for each side of the body.-Right superior intercostal vein:...
, the lower vessels by the hemiazygos vein
Hemiazygos vein
The hemiazygos vein is a vein running superiorly in the lower thoracic region, just to the left side of the vertebral column.-Structure:...
.
Opposite the heads of the ribs, the sympathetic trunk
Sympathetic trunk
The sympathetic trunks are a paired bundle of nerve fibers that run from the base of the skull to the coccyx.-Structure:...
passes downward in front of them, and the splanchnic nerves
Splanchnic nerves
The splanchnic nerves are paired nerves that contribute to the innervation of the viscera, carrying fibers of the autonomic nervous system as well as sensory fibers from the organs...
also descend in front by the lower arteries.
Each artery then divides into an anterior and a posterior ramus.
A given posterior intercostal artery travels along the bottom of the rib with its corresponding posterior intercostal vein, as well as the intercostal nerve of the given space. The vein is superior to the artery, and the intercostal nerve is inferior to it. Commonly, the mnemonic, "Van," is used to recall the order of the vein, artery and nerve, from superior to inferior.