Posterior Thoracic Wall

Structures of the posterior thoracic wall are those not contained within pleural cavities or mediastinal compartments, but rather lie deep to the endothoracic fascia (Fig. 1). Structures of the posterior thoracic wall include:
• Branches of the thoracic (descending) aorta-posterior intercostal arteries
• Tributaries of the azygos venous system- posterior intercostal veins

• Thoracic sympathetic trunks with rami communicantes
• Anterior rami (intercostal nerves)
• Subcostal muscles-innermost intercostal muscles that span more than one intercostal space.
lntercostal veins, arteries, and nerves travel in the intercostal space between the internal and innermost intercostal muscles. Bilateral thoracic sympathetic trunks run vertically just lateral to thoracic vertebral bodies T1 through T12. Gray and white rami communicantes connect the sympathetic trunk to spinal nerves at each spinal level in this region.

Figure 1: Posterior thoracic wall. Aorta ghosted to highlight azygos system.