Relationship of radius to pressure along the aorta in living dogs

The instantaneous pressure-radius relationship and mean dimensions were studied at various sites along the aorta in 30 dogs. The pressure-radius relationship was studied in the living state using an electrical caliper to measure the radius continuously through the cardiac cycle. The relative dimensions of the aortic tree at branching sites were calculated from Jeltrate casts made immediately post mortem. The results indicate: 1) The value of ΔR/ΔP and the mean radius decreased with distance along the aorta. 2) The calculated value for E p , the “pressure-strain elastic modulus” increased monotonically from the ascending aorta to the bifurcation. 3) An “average” arterial tree was constructed from the mean values of the radius obtained from the caliper data and the branching ratios obtained from the casts. elastic properties, aorta; dimensions, dog aorta Submitted on March 5, 1963