Posterior intercostal veins

Diagram of the posterior intercostal veins.

The posterior intercostal veins are a group of veins that drain the intercostal spaces of the thoracic cavity. These veins are part of the systemic circulation and play a crucial role in returning deoxygenated blood from the thoracic wall to the heart.

Anatomy

The posterior intercostal veins are located in the intercostal spaces, which are the spaces between the ribs. Each intercostal space contains a posterior intercostal vein, artery, and nerve, which run along the inferior border of the rib above.

Course

The posterior intercostal veins originate from the intercostal muscles and the parietal pleura. They travel posteriorly and superiorly, running alongside the posterior intercostal arteries.

Drainage

The posterior intercostal veins drain into the azygos vein system. Specifically, the veins from the right side of the thorax drain into the azygos vein, while those from the left side drain into the hemiazygos vein or the accessory hemiazygos vein.

Function

The primary function of the posterior intercostal veins is to collect deoxygenated blood from the intercostal spaces and return it to the heart. This is part of the larger process of systemic venous return, which is essential for maintaining the circulation of blood throughout the body.

Clinical Significance

The posterior intercostal veins can be involved in various clinical conditions. For example, they may become engorged in cases of superior vena cava syndrome, where the normal flow of blood through the superior vena cava is obstructed. Additionally, these veins can be a site for the spread of metastatic cancer from the thoracic wall.

Related pages

• Azygos vein
• Hemiazygos vein
• Intercostal muscles
• Thoracic cavity