Three-dimensional organisation of the vasculature of the rat spermatic cord and testis. A scanning electron-microscopic study of vascular corrosion casts.

The vascular architecture of the rat testis and spermatic cord was studied by a corrosion cast technique combined with scanning and transmission electron microscopy, and light microscopy. The casts preserve the endothelial impressions of the vessels and enable them to be differentiated into the various vascular components. Frequent arterio-arterial anastomotic arcades and occasional arteriovenous anastomotic channels are seen. A well defined hexagonal pattern of intertubular and peritubular vessels surround the seminiferous tubules. Prominent large endothelial nuclei protrude into the arterial lumina at branching sites, but their functional significance is not known. The outer-most vascular layer of the testis consists of large veins, venules, and capillaries, but lacks any arterial branches; it also contains loosely arranged veno-venous anastomotic networks. We have named this vascular layer the sub-albugineal venous plexus. The testicular artery increases in luminal diameter as it approaches the testis. The periarterial capillary plexus, which lies between the pampiniform plexus and the testicular artery, is drained by two types of venules.