VASA VASORUM OF SUPERFICIAL COLLECTING LYMPHATICS OF HUMAN THIGH

Abstract

Collecting lymphatics were obtained from human thigh fat for light microscopy andtridimensional reconstruction at time of operation for varicose veins. No patient hadlymphedema and routine sections showed no inflammation or notable pathologic alteration ofthe surrounding soft tissue. Abundant vasa vasorum was observed around the musculature ofsuperficial collecting lymphatics of human thigh. Within intervalvular portions of the lymphaticcollectors where the muscle coat was thicker and more compact, the vasa vasorum penetratedbetween smooth muscle cells and was in contact with the endothelium. In valvular portions of thecollecting lymphatics where the muscle layer was thinner and more fragmented, there were fewervasa vasorum. Tri-dimensional reconstructions of the collecting lymphatic wall showed twocommunicating plexi of vasa vasorum—one outside and the other inside the muscle layer.Arteries and veins of similar size did not have such an abundant vasa vasorum. The explanationfor this difference may relate to the fact that a relatively low oxygen and nutrient content oflymph is insufficient to nourish the collecting lymphatic. Moreover, diffusion of nutrients fromthe external plexus is likely also impeded by the thickness and density of the muscle layer. Thevasa vasorum deep in the muscular layer and in the subendothelial space probably sustainadequate nutrition and oxygenation to the collecting lymphatic.