Veins of the thoracic wall (Latin)

The venous drainage of the thoracic wall is accommodated by vv. intercostales that accompany the aa. intercostales. Anteriorly, there are nine vv. intercostales anteriores that drain into the v. musculophrenica or v. interna thoracica. On the lateroposterior aspect, there are eleven vv. intercostales posteriores and the v. subcostalis. Most of the vv. intercostales posteriores drain directly into the azygos venous system (right 4th-11th ➝ v. azygos, left 4th-7th ➝ v. hemiazygos accessoria, left 8th-11th ➝ v. hemiazygos). The uppermost, v. intercostalis suprema on either side drains directly into the ipsilateral v. brachiocephalica. Additionally, the vv. intercostales posteriores 2-3 merge to form a v. intercostalis superior on each side. The left v. intercostalis superior goes on to drain into the v. brachiocephalica sinistra, while the right one drains into the v. azygos.