Anatomical Structure and Location of the Posterior Intercostal Veins

Description

Along the inferior margins of each rib, the posterior intercostal veins course within the costal groove, accompanying the posterior intercostal arteries and intercostal nerves in the neurovascular plane between the internal and innermost intercostal muscles. A lateral to posterolateral thoracic view brings the vertebral column into orientation, so the veins can be followed medially toward the heads and necks of the ribs at the thoracic vertebrae. From there, the segmental veins converge posteriorly into the azygos system on the right and into the hemiazygos and accessory hemiazygos channels on the left, with cross-communications typically occurring behind the aorta and esophagus. Mapping these posterior intercostal veins to their azygos drainage matters any time you work near the posterior mediastinum. The same pathways enlarge in azygos continuation of the inferior vena cava, and they are a frequent source of collateral flow in SVC obstruction, so recognizing their segmental pattern helps interpret venous engorgement on CT or venography. Surgeons also care because posterior intercostal vessels are exposed during posterolateral thoracotomy and VATS port placement, and they can bleed briskly when injured at the rib’s inferior border. Use this illustration for gross anatomy teaching of the thoracic wall, for radiology primers that correlate intercostal neurovascular bundles with axial CT landmarks, or for cardiothoracic surgery materials explaining posterior mediastinal venous collaterals and azygos anatomy. Clear, practical topography. Anatomical accuracy verified by SciePro's Medical Advisory Board.