Nerves and Blood Vessels of the Thoracic Wall

Nerves Intercostal nerves Are the anterior primary rami of the first 11 thoracic spinal nerves. The anterior primary ramus of the twelfth thoracic spinal nerve is the subcostal nerve , which runs beneath the twelfth rib. Run between the internal and innermost layers of muscles, with the intercostal veins and arteries above (Veins, Arteries, Nerves [VAN ]). Are lodged in the costal grooves on the inferior surface of the ribs. Give rise to lateral and anterior cutaneous branches and muscular branches Arteries Internal thoracic artery Usually arises from the first part of the subclavian artery and descends directly behind the first six costal cartilages, just lateral to the sternum. Gives rise to two anterior intercostal arteries in each of the upper six intercostal spaces and terminates at the sixth intercostal space by dividing into the musculophrenic and superior epigastric arteries. Pericardiophrenic artery Accompanies the phrenic nerve between the pleura and the pericardium to the diaphragm. Supplies the pleura, pericardium, and diaphragm (upper surface). Anterior intercostal arteries Are 12 small arteries , 2 in each of the upper six intercostal spaces that run laterally, 1 each at the upper and lower borders of each space. The upper artery in each intercostal space anastomoses with the posterior intercostal artery, and the lower one joins the collateral branch of the posterior intercostal artery. Provide muscular branches to the intercostal, serratus anterior, and pectoral muscles Anterior perforating branches Perforate the internal intercostal muscles in the upper six intercostal spaces, course with the anterior cutaneous branches of the intercostal nerves, and supply the pectoralis major muscle and the skin and subcutaneous tissue over it. Provide the medial mammary branches (second, third, and fourth branches). Musculophrenic artery Follows the costal arch on the inner surface of the costal cartilages. Gives rise to two anterior arteries in the seventh, eighth, and ninth spaces; perforates the diaphragm; and ends in the tenth intercostal space, where it anastomoses with the deep circumflex iliac artery. Supplies the pericardium, diaphragm, and muscles of the abdominal wall. Superior epigastric artery Descends on the deep surface of the rectus abdominis muscle within the rectus sheath; supplies this muscle and anastomoses with the inferior epigastric artery. Supplies the diaphragm, peritoneum, and anterior abdominal wall. Internal thoracic vein Is formed by the confluence of the superior epigastric and musculophrenic veins, ascends on the medial side of the artery, receives the upper six anterior intercostal and pericardiacophrenic veins, and ends in the brachiocephalic vein. Thoracoepigastric vein Is a venous connection between the lateral thoracic vein and the superficial epigastric vein. ◄.....Go back to the Gross Anatomy homepage