TY - CHAP M1 - Book, Section TI - Chronic Venous Disease of the Upper Extremities and Central Veins A1 - Gober, Leah A1 - Illig, Karl A. A2 - Nazzal, Munier A2 - Blebea, John A2 - Osman, Mohamed F. PY - 2024 T2 - Vascular and Endovascular Surgery: Clinical Diagnosis and Management AB - The venous system, with its complex network of one-way valves, communicating branches, and peripheral pumping mechanisms, connects in a progressive fashion that culminates in an effective system to return blood to the heart even when working against gravity. Venous embryologic development is understood as passing through three main stages: first, as an undifferentiated capillary network composed of primitive mesenchymal tissues; second, differentiation into large plexiform structures; and third, maturation into isolated macroscopic channels, the vein.1,2 The upper extremity, in particular, is unique in that it needs to return blood while being located intermittently both above and below the right atrium to which it flows.3 SN - PB - McGraw Hill CY - New York, NY Y2 - 2024/03/29 UR - accesssurgery.mhmedical.com/content.aspx?aid=1200677188 ER -