Vv. intercostales posteriores, the posterior intercostal veins, are accompanied in the intercostal spaces of the same-named artery by one vein to each artery. About the confluence of the intercostal veins into the unpaired and semi-separ veins mentioned above. The ramus dorsalis (a branch carrying blood from the deep muscles of the back) and ramus spinalis (from the veins of the vertebral plexuses) flow into the posterior ends of the intercostal veins near the spine.
V. thoracica interna, the internal thoracic vein, accompanies the artery of the same name; being double for the most part of the extension, it, however, merges near I rib into one trunk, which flows into v. brachiocephalica of the same side.
The initial section of her, v. epigastrica superior, anastomoses with v. epigastrica inferior (infused in v. iliaca externa), as well as with the subcutaneous veins of the abdomen (vv. subcutaneae abdominis), forming a large mesh of the subcutaneous tissue. From this network, blood flows upward through v. thoracoepigastrica and v. thoracica lateralis in v. axillaris, and downward blood flows through v. epigastrica superficialis and v. circumflexa ilium superficialis in the femoral vein. Thus, the veins in the anterior abdominal wall form a direct connection of the branching areas of the upper and lower hollow veins. In addition, in the navel several venous branches are connected by means of vv. paraumbilicales with portal vein system (see below for more on this).