Collecting lymphatics were obtained from human thigh fat for light mic
roscopy and tridimensional reconstruction at time of operation for var
icose veins. No patient had lymphedema and routine sections showed no
inflammation or notable pathologic alteration of the surrounding soft
tissue. Abundant vasa vasorum was observed around the musculature of s
uperficial collecting lymphatics of human thigh. Within intervalvular
portions of the lymphatic collectors where the muscle coat was thicker
and more compact, the vasa vasorum penetrated between smooth muscle c
ells and was in contact with the endothelium. In valvular portions of
the collecting lymphatics where the muscle layer was thinner and more
fragmented, there were fewer vasa vasorum. Tri-dimensional reconstruct
ions of the collecting lymphatic wall showed two communicating plexi o
f vasa vasorum - one outside and the other inside the muscle layer. Ar
teries and veins of similar size did not have such an abundant vasa va
sorum. The explanation for this difference may relate to the fact that
a relatively low oxygen and nutrient content of lymph is insufficient
to nourish the collecting lymphatic. Moreover, diffusion of nutrients
from the external plexus is likely also impeded by the thickness and
density of the muscle layer. The vasa vasorum deep in the muscular lay
er and in the subendothelial space probably sustain adequate nutrition
and oxygenation to the collecting lymphatic.