Microvasculature of the human testis and excurrent duct system. Resin-casting and scanning electron-microscopic studies.

The vascular microarchitecture of the human testis and excurrent duct system was examined by use of a casting method combined with scanning electron microscopy. In the testicular parenchyma, the capillaries form a fine plexus around the seminiferous tubules. The commonly described rope-ladder-like pattern of the peritubular capillaries is absent in the human testis. The microvasculature of the rete testis consists of a poorly organized plexus. Throughout the epididymis including the ductuli efferentes, the peritubular capillary network encircles each tubule cylindrically. In the cauda epididymidis, a coarse venous network surrounds the capillary network externally. Small arteries of the epididymis not only penetrate the connective tissue septa, but also run along the surface. In the ductus deferens, three distinct microvascular systems are distinguished: (1) a venous network located in the connective tissue surrounding the muscular coat, (2) a microvascular plexus within the muscular coat, and (3) a peritubular capillary network. The plexus within the muscular coat interconnects the venous and the peritubular capillary networks.