VENOUS CHEST ANATOMY - CLINICAL IMPLICATIONS

This article provides a practical approach to the clinical implication s and importance of understanding the collateral venous anatomy of the thorax. Routine radiography, conventional venography, computed tomogr aphy (CT), and magnetic resonance (MR) imaging studies provide correla tive anatomic models for the demonstration of how interconnecting coll ateral vascular networks within the thorax maintain venous stability a t all times. Five major systems comprise the collateral venous network of the thorax (Fig. 1). These include the paravertebral, azygos-hemia zygos, internal mammary, lateral thoracic, and anterior jugular venous systems (AJVS). The five systems are presented in the following seque nce: (a) a brief introduction to the importance of catheter position a nd malposition in understanding access to the thoracic venous system, (b) the anatomy of the azygos-hemiazygos systems and their relationshi p with the paravertebral plexus, (c) the importance of the AJVS, (d) ' loop' concepts interconnecting the internal mammary and azygos-hemiazy gos systems by means of the lateral thoracic and intercostal veins, an d (e) the interconnecting venous networks on the thoracic side of the thoracoabdominal junction. Certain aspects of the venous anatomy of th e thorax will not be discussed in this chapter and include (a) the int ra-abdominal anastomoses between the superior and inferior vena cavae (IVC) via the internal mammary, lateral thoracic, and azygos-hemiazygo s systems (beyond the scope of this article), (b) potential collateral vessels involving vertebral, parascapular, thyroidal, thymic, and oth er smaller veins that might anastomose with the major systems, and (c) anatomic variants and pitfalls that may mimic pathologic conditions ( space limitations). (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.