This investigation was undertaken to establish
firmly the existence of dorsal arterial anastomoses
in the normal Wistar rat. Selected information
was obtained on regional locations,
numbers, densities, and sizes of the anastomoses
and patterns of the involved collateral
arterioles. Such structural information is considered
necessary to evaluate change, or detect
lack of it, in these anastomoses and collaterals
when attempts are made to increase the collateral
circulation.