Shrinkage of dog lobes during air-drying fixation

Air-drying of canine lung lobes, distended at a constant pressure corresponding to 50% of lobar total lung capacity, resulted in a volume shrinkage of 35.8%. To examine associated changes in shape of the lobes, the shrinkage of three orthogonal directions (x, y, and z) was quantitated by measuring the change in length per unit length (strain; epsilon) of straight lines between pleural markers. Epsilon x = 0.14, epsilon y = 0.22, and epsilon z = 0.12. This inequality of strains indicated that moderate shape changes occurred. The direction of the largest strain component (epsilon y) corresponded to a direction normal to the largest projected surface area of the lobe.