Thoracic duct (TD) has endothelial wall in embryo of 7 week with first endothelial valves in embryo of 8 week. It transformates into multi-layered TD wall in ending of human uterine development when thickness of the wall increases in a 20 times. Uneven growth of TD wall connects with its gistogenesis intimately. Correlation of thickness of TD wall and width of its lumen is less 0,05 before 12 weeks of uterine human life what permit to regard TD as thin-walled vessel. In fetuses of 4-5 months TD become thick-walled vessel. Inner layers of TD wall try the largest tension under inner pressure and stretch more than outer layers. Moreover subendothelial layer of connective tissue remains thin and crumbly with net of thin retcular fibres. Their thickness increases in broaden and compacted outer layer where first collagen fibres appear. The first smooth myocyties appear, muscular coat forms on boundary between layers with diferrent hard. The coat brakes moving distortion (relative displacement of layers) and prevents destruction of TD wall. Lymph from TD lumen penetrates through endothelium into connective tissue and erodes it, brakes weak intermolecular connections, slows down fibregenesis. Speed of diffusion diminishs rapidly in thickness of the wall. And thus subendothelial layer of connective tissue remains thin and plastic. Outer coat of TD promotes new formation and growth of valves because it slows down outer dilatation of TD and stabilizes structures of residual deformation. Muscular coat limits dilatation of TD and stretching of inner layers of TD wall, its folden deformation. Thus uneven growth is in the base of TD morfogenesis and gistogenesis.
The work is submitted to the International Scientific Conference «Innovative Medical Technology», Moscow-Paris, March 18-25, 2011, came to the editorial office оn 19.01.2011.