4 Neurovascular Systems: Forms and Relations
4.1 The Arteries
A Overview of the arteries of the trunk wall
The arrangement of the neurovascular structures in the trunk reflects the segmental anatomy of the trunk wall, particularly in the thoracic region. Accordingly, each of the intercostal spaces is traversed by an intercostal artery, vein, and nerve.
The chest wall is supplied principally by the posterior intercostal arteries, which arise from the aorta, and by anterior intercostal branches arising from the internal thoracic artery:
• The first and second posterior intercostal arteries, which are given off by the superior intercostal artery (= branch of the costocervical trunk, see D a)
• The third through eleventh posterior intercostal arteries (each giving off a dorsal, a collateral, and a lateral cutaneous branch, see D b)
• The musculophrenic artery (one of the two terminal branches of the internal thoracic artery), which runs behind the costal arch, see B
• The subcostal artery (twelfth intercostal artery), see B
• The anterior intercostal arteries, which arise from the internal thoracic artery, see B
Many other “regional” arteries supply the anterior, lateral, and posterior trunk wall.
Anterior trunk wall
• The perforating branches (from the internal thoracic artery, e.g., the medial mammary branches that supply the breast), see D b
• The superior epigastric artery (continuation of the internal thoracic artery, see B and C)
• The inferior epigastric artery (from the external iliac artery, see B and C)
• The superficial epigastric artery, see B
• The superficial circumflex iliac artery, see B
• The deep circumflex iliac artery, see B
Posterior trunk wall
• Dorsal branches (from the posterior intercostal arteries), each with a medial, a lateral cutaneous, and a spinal branch, see D c
• The first through fourth lumbar arteries (each with a dorsal and spinal branch), see B
• The median sacral artery, see B
Lateral trunk wall
• The superior thoracic artery, see B
• The thoracoacromial artery, see B
• The lateral thoracic artery, see B
• The lateral cutaneous branches (from the intercostal arteries), which distribute branches mainly to the breast (lateral mammary branches, see D b)
• The iliolumbar artery (from the internal iliac artery), which gives off an iliac, a lumbar, and a spinal branch, see B
B Arteries of the trunk wall
Anterior view. The anterior portions of the ribs have been removed on the left side.
D Course and branches of the intercostal arteries
a Anterior view of the superior intercostal artery, which gives off the first two intercostal arteries.
Note: The first and second posterior intercostal arteries are not branches of the thoracic aorta but arise from the superior intercostal artery (branch of the costocervical trunk), which are branches of the subclavian artery.
b Anterior view of the posterior intercostal arteries that are segmental branches of the thoracic aorta.
Note: The anterior intercostal arteries arise from the subclavian artery (via the internal thoracic artery), while the posterior intercostal arteries arise directly from the thoracic aorta.
c Branches of the posterior intercostal arteries, viewed from the superior view.
4.2 The Veins
A Overview of the veins of the trunk wall
The veins of the trunk wall drain into both the vena caval and azygos systems (see B). Within the vena caval system, we can distinguish between the tributary regions of the inferior vena cava and the superior vena cava. Connections between the superior and inferior vena cavae are called cavocaval anastomoses (collateral channels).