constitutional_part_of regional_part_of Vasculature of body Systemic venous system Systemic venous tree organ Inferior systemic venous tree FMA:82673 Inferior vena caval tree Lower systemic venous tree fma ystemic venous tree (organ) the trunk of which, the inferior vena cava, continues with the right atrium and the branches of which are distributed to the abdomen, pelvis, perineum and the lower limbs. Examples: There is only one inferior systemiv venous tree.