Microvascular structure of the human epididymis.
The microvascular anatomy of the human epididymal duct system from rete testis to vas deferens was studied using microangiography and histology. Various segments of the duct system show significant differences in the density and arrangement of the small blood vessels. The rete testis is poorly vascularized while the first lobulated segment of the epididymis, which is formed by the efferent ducts is provided with a dense subepithelial capillary bed. The more distal segments of the epididymis have less dense capillarization surrounding the epididymal duct. In the vas deferens the blood vessels form a double capillary network. The outer capillary network surrounds the smooth muscle layers and the inner is located immediately beneath the duct epithelium. The organization of blood capillaries in the human epidymis and the differences seen in different portions of the excurrent duct system follow basically the general pattern seen in some experimental animals.