Posterior intercostal veins
Encyclopedia
The posterior intercostal veins are veins that drain the intercostal space
s 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 dorsal branch that drains blood from the muscles of the back.
There are eleven posterior intercostal veins on each side. Their patterns are variable, but they are commonly arranged as:
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 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 dorsal branch that drains blood from the muscles of the back.
There are eleven posterior intercostal veins on each side. Their patterns are variable, but they are commonly arranged as:
- The 1st posterior intercostal vein, supreme intercostal veinSupreme intercostal veinThe supreme intercostal vein is a paired vein that drains the first intercostal space on its corresponding side.It usually drains into the brachiocephalic vein...
, drains into the brachiocephalic veinBrachiocephalic veinThe left and right brachiocephalic veins in the upper chest are formed by the union of each corresponding internal jugular vein and subclavian vein...
or the vertebral veinVertebral veinThe vertebral vein is formed in the suboccipital triangle, from numerous small tributaries which spring from the internal vertebral venous plexuses and issue from the vertebral canal above the posterior arch of the atlas....
. - The 2nd and 3rd (and often 4th) posterior intercostal veins drain into the superior intercostal veinSuperior intercostal veinThe 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 remaining posterior intercostal veins drain into the azygos veinAzygos veinThe 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, or the hemiazygos veinHemiazygos veinThe hemiazygos vein is a vein running superiorly in the lower thoracic region, just to the left side of the vertebral column.-Structure:...
on the left.