Dorsal Branches of the Posterior Intercostal Veins, Lateral View

Description

Running along the lateral thoracic wall, the posterior intercostal veins course within each intercostal space along the inferior border of the ribs, accompanied by the posterior intercostal arteries and the intercostal nerves in the costal groove. Dorsal branches leave the main intercostal venous trunks near the angles of the ribs and pass posteriorly toward the paraspinal region, tracking adjacent to the corresponding dorsal branches of the posterior intercostal arteries. Rib cage, thoracic vertebrae, and scapula form the bony frame, with vessels positioned deep to the superficial thoracic musculature and aligned segmentally from superior to inferior interspaces. Relationships are the point. Clinically, the dorsal branches matter because they communicate with the vertebral venous plexuses and sit near common access corridors for thoracic and posterior spinal procedures, where unexpected bleeding can obscure the field. Their close pairing with the posterior intercostal arteries also reinforces the neurovascular bundle arrangement that guides safe needle and trocar placement, since staying near the superior margin of a rib reduces the chance of injuring the vein and artery in the groove. This lateral perspective also helps clarify why segmental thoracic venous drainage varies, with right-sided channels often favoring the azygos system and left-sided channels the hemiazygos and accessory hemiazygos pathways. Use this illustration for gross anatomy and regional anatomy teaching on the thoracic wall, especially labs that pair rib osteology with the intercostal neurovascular bundle, or for surgical education materials covering chest tube insertion, posterolateral thoracotomy planes, and paraspinal exposure. It also suits textbooks and review articles discussing collateral venous pathways around the thoracic spine and azygos system anatomy. Anatomical accuracy verified by SciePro's Medical Advisory Board.