Isometric growth of lungs and airways?
We have concluded earlier why standing height is not an ideal index for scaling changes in the dimensions of organs during growth. That does not necessarily imply that lungs and airways cannot grow isometrically, in which case the infant lung can be regarded is a mirror image of the adult lung. In the case of isometric growth the length and the diameter of airways, and the lung volume, grow proportionally.
How can we address this issue? Here is one way. As we discuss elsewhere large intrathoracic airways are compressed during a forced expiration. We have also concluded that materials should be able to deal with comparable elastic loads (such as occur during bending or stretching), independent of their dimensions; it seems appropriate to also apply this requirement to airways. This offers an interesting opportunity to study whether lungs and airways grow isometrically, by making use of data obtained during a forced expiration.