The intercostal arteries are a group of

arteries An artery () is a blood vessel in humans and most other animals that takes oxygenated blood away from the heart in the systemic circulation to one or more parts of the body. Exceptions that carry deoxygenated blood are the pulmonary arteries in ...

passing within an

intercostal space The intercostal space (ICS) is the anatomic space between two ribs (Lat. costa). 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 kind ...

(the space between two adjacent ribs). There are 9 anterior and 11 posterior intercostal arteries on each side of the body. The anterior intercostal arteries are branches of the

internal thoracic artery The internal thoracic artery (ITA), also known as the internal mammary artery, is an artery that supplies the anterior chest wall and the breasts. It is a paired artery, with one running along each side of the sternum, to continue after its bifurc ...

and its terminal branchthe

musculophrenic artery The intercostal arteries are a group of arteries passing within an intercostal space (the space between two adjacent ribs). There are 9 anterior and 11 posterior intercostal arteries on each side of the body. The anterior intercostal arteries a ...

. The posterior intercostal arteries are branches of the supreme intercostal artery and

thoracic aorta The thoracic aorta is a part of the aorta located in the thorax. It is a continuation of the aortic arch. It is located within the posterior mediastinal cavity, but frequently bulges into the left pleural cavity. The descending thoracic aorta be ...

. Each anterior intercostal artery

anastomoses An anastomosis (, : anastomoses) is a connection or opening between two things (especially cavities or passages) that are normally diverging or branching, such as between blood vessels, leaf#Veins, leaf veins, or streams. Such a connection may be ...

with the corresponding posterior intercostal artery arising from the thoracic aorta.

Anterior intercostal arteries

Origin

The upper six anterior intercostal arteries are branches of the

(anterior intercostal branches of internal thoracic artery). The internal thoracic artery then divides into its two terminal branches, one of which - the

- proceeds to issue anterior intercostal arteries to the remaining 7th, 8th, and 9th intercostal spaces; these diminish in size as the spaces decrease in length.

Course and relations

They are at first situated between the

pleurae The pleurae (: pleura) are the two flattened closed sacs filled with pleural fluid, each ensheathing each lung and lining their surrounding tissues, locally appearing as two opposing layers of serous membrane separating the lungs from the media ...

and the

intercostales interni The internal intercostal muscles (intercostales interni) are a group of skeletal muscles located between the ribs. They are eleven in number on either side. They commence anteriorly at the sternum, in the intercostal spaces between the cartilages ...

, and then between the mm. intercostales interni et intimi.

Distribution

They supply the

intercostal muscles The intercostal muscles comprise many different groups of muscles that run between the ribs, and help form and move the chest wall. The intercostal muscles are mainly involved in the mechanical aspect of breathing by helping expand and shrink th ...

and, by branches which perforate the

intercostales externi The external intercostal muscles or external intercostals (intercostales externi) are eleven in number on both sides. Structure The muscles extend from the tubercles of the ribs behind, to the cartilages of the ribs in front, where they end ...

, the

pectoral muscles Pectoral muscles (colloquially referred to as "pecs") are the muscles that connect the front of the human chest with the bones of the upper arm and shoulder. This region contains four muscles that provide movements to the upper limbs or ribs. P ...

and the

mamma Mama(s) or Mamma or Momma may refer to: Roles *Mother, a female parent *Mama-san, in Japan and East Asia, a woman in a position of authority *Maternal uncle, in some parts of South Asia Places *Mama, Russia, an urban-type settlement in the Mamsk ...

Posterior intercostal arteries

There are eleven posterior intercostal arteries on each side. Each artery divides into an anterior and a posterior ramus.

Origin

* The 1st and 2nd posterior intercostal arteries arise from the supreme intercostal artery, a branch of the

costocervical trunk The costocervical trunk arises from the superior and posterior part of the second part of subclavian artery, behind the scalenus anterior on the right side, and medial to that muscle on the left side. Passing backward, it splits into the deep ...

of the

subclavian artery In human anatomy, the subclavian arteries are paired major arteries of the upper thorax, below the clavicle. They receive blood from the aortic arch. The left subclavian artery supplies blood to the left arm and the right subclavian artery suppli ...

. The SICA descends vertically. It passes lateral to the

cervicothoracic ganglion The stellate ganglion (or cervicothoracic ganglion) is a sympathetic ganglion formed by the fusion of the inferior cervical ganglion and the first thoracic (superior thoracic sympathetic) ganglion, which is present in 80% of individuals. Sometimes ...

. It passes in between the pleural cupula, and anterior border of the neck of rib I. It then passes anterior to the necks of ribs II-III. * The remaining nine arteries arise from (the posterior aspect of) the

Course and relations

Each posterior intercostal artery travels along the bottom of the rib alongside its corresponding

posterior intercostal vein The posterior intercostal veins are veins that drain the intercostal spaces posteriorly. They run with their corresponding posterior intercostal artery on the underside of the rib, the vein superior to the artery. Each vein also gives off a dorsa ...

and

intercostal nerve The intercostal nerves are part of the somatic nervous system, and arise from the anterior rami of the thoracic spinal nerves from T1 to T11. The intercostal nerves are distributed chiefly to the thoracic pleura and abdominal peritoneum, and d ...

; the vein is superior to the artery, and the nerve is inferior to it. The mnemonic "VAN" is commonly used to recall their order from superior to inferior. 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 Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spinal ...

behind the

esophagus The esophagus (American English), oesophagus (British English), or œsophagus (Œ, archaic spelling) (American and British English spelling differences#ae and oe, see spelling difference) all ; : ((o)e)(œ)sophagi or ((o)e)(œ)sophaguses), c ...

thoracic duct In human anatomy, the thoracic duct (also known as the ''left lymphatic duct'', ''alimentary duct'', ''chyliferous duct'', and ''Van Hoorne's canal'') is the larger of the two lymph ducts of the lymphatic system (the other being the right lymph ...

, and

azygos vein The azygos vein (from Ancient Greek ἄζυγος (ázugos), meaning 'unwedded' or 'unpaired') is a vein running up the right side of the thoracic vertebral column draining itself towards the superior vena cava. It connects the systems of superio ...

, and are covered by the right

lung The lungs are the primary Organ (biology), organs of the respiratory system in many animals, including humans. In mammals and most other tetrapods, two lungs are located near the Vertebral column, backbone on either side of the heart. Their ...

and

pleura The pleurae (: pleura) are the two flattened closed sacs filled with pleural fluid, each ensheathing each lung and lining their surrounding tissues, locally appearing as two opposing layers of serous membrane separating the lungs from the med ...

. The left aortic intercostals run backward on the sides of the vertebrae and are covered by the left

and

; the upper two vessels are crossed by the left

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 right superior intercostal vein drains the 2nd, 3rd, and 4th posterior inter ...

, the lower vessels by the

hemiazygos vein The hemiazygos vein (vena azygos minor inferior) is a vein running superiorly in the lower thoracic region, just to the left side of the vertebral column. Structure The hemiazygos vein and the accessory hemiazygos vein, when taken together, esse ...

. The

sympathetic trunk The sympathetic trunk (sympathetic chain, gangliated cord) is a paired bundle of nerve fibers that run from the base of the skull to the coccyx. It is a major component of the sympathetic nervous system. Structure The sympathetic trunk lies just ...

(opposite the heads of the ribs) and

splanchnic nerves The splanchnic nerves are paired visceral nerves (nerves that contribute to the innervation of the internal organs), carrying fibers of the autonomic nervous system ( visceral efferent fibers) as well as sensory fibers from the organs ( visceral ...

pass anterior to the arteries.

References

External links

* - "

Thoracic wall The thoracic wall or chest wall is the boundary of the thoracic cavity. Structure The bony skeletal part of the thoracic wall is the rib cage, and the rest is made up of muscle, skin, and fasciae. The chest wall has 10 layers, namely (from su ...

: Branches of the Internal Thoracic Artery" * http://www.instantanatomy.net/thorax/vessels/aupperintercostalarteries.html * - "Branches of the ascending aorta, arch of the aorta, and the descending aorta." * () * {{Authority control Arteries of the thorax Medical mnemonics

Anterior intercostal arteries

Origin

Course and relations

Distribution

Posterior intercostal arteries

Origin

Course and relations

See also

References

External links