Dorsal Branches of Posterior Intercostal Veins, Posterior View

Description

Arising from the posterior intercostal veins along the costal grooves, the dorsal branches course posteriorly to pierce the internal intercostal and overlying musculature, then run medially and inferiorly toward the paravertebral region. Posterior to the rib cage, these veins lie deep to trapezius and rhomboid major and minor near the medial border of the scapula, with segments tracking between erector spinae components and the costotransverse region. Small venules from the posterior thoracic wall converge into larger dorsal tributaries that drain back into the posterior intercostal trunks lateral to the spinous processes. Orientation is clear. Clinically, dorsal venous drainage matters because the posterior intercostal veins communicate with the vertebral venous plexuses, creating a low pressure collateral route that can enlarge with azygos system obstruction or superior vena cava syndrome. Surgeons working posterolaterally on the thorax, including during thoracotomy, rib fracture fixation, or posterior spinal exposure near the costovertebral joints, must anticipate these vessels as they traverse the intercostal spaces and approach the paraspinal gutter. Their proximity to the intercostal neurovascular bundle also makes this anatomy relevant when teaching safe planes for paravertebral block or intercostal procedures. Ideal for thoracic anatomy and back dissection teaching in gross anatomy, this plate also supports atlas chapters on thoracic wall vasculature and clinical figures for texts covering collateral venous pathways and paravertebral approaches. Radiology educators can pair it with contrast enhanced CT or MR discussions of azygos and vertebral plexus drainage patterns to help learners map posterior intercostal venous anatomy onto axial imaging. Anatomical accuracy verified by SciePro's Medical Advisory Board.