Lateral Branches of the Intercostal Arteries, Anterior View

Description

Arising from the posterior intercostal arteries and coursing within the costal grooves, the intercostal vessels track along the inferior margins of the ribs, then give off prominent lateral cutaneous branches that pierce the internal intercostal and external intercostal muscles near the midaxillary line. From an anterior angle, these perforating branches can be followed as they emerge through the thoracic wall and fan superficially toward the lateral thorax, with the sternum and costal cartilages providing a fixed midline reference. The rib cage, clavicles, and upper sternum frame the vascular pattern, while the paired internal thoracic (internal mammary) vessels descend parasternal and help orient right from left. For procedural anatomy, the lateral branches matter because they mark where segmental blood supply exits the intercostal spaces to reach skin, serratus anterior, and the lateral mammary region, territories that become relevant in thoracostomy, lateral thoracotomy incisions, and flap design. Their relationship to the rib’s inferior border reinforces a classic point: intercostal neurovascular bundles lie protected in the costal groove, so chest tube insertion is taught just superior to the rib to reduce injury, yet the lateral cutaneous branches remain at risk when you dissect through the lateral thoracic wall. Bleeding from an injured intercostal artery can be brisk and difficult to control in the deep space. Use this plate in gross anatomy and regional thorax courses to teach segmental vascular anatomy against the bony landmarks, or in surgical education materials covering tube thoracostomy, intercostal nerve blocks, and lateral chest wall approaches. It also fits well in radiology and trauma publications that correlate rib fractures with intercostal vessel injury patterns and hemothorax risk. Anatomical accuracy verified by SciePro's Medical Advisory Board.