The vascular injection method and the functional geometry of the microcirculation.

The silicone elastomer microvascular casting method is readily adaptable for study of most microcirculatory beds. These perfusion materials are not acutely toxic to the microcirculation. The basic microvascular geometry can be profitably studied with this method and it demonstrates a pattern of right-angle branching in the lung, a manifold pattern at the inflow of the renal glomerulus, and a web or netlike capillary bed in the renal pelvis. Silicone rubber perfusion permits the retention of the in vivo physiological state of the blood vessels at the time of perfusion to make possible precise measurement of vessel diameters and examination of the blood vessel wall.