I trust nowadays singers don’t give too much attention to a such valuable part of the singers “mechanism” as diaphragm.
I am delighted to share with you these brilliant videos where you can clearly see how powerful diaphragm is as a muscle and how significantly it can change size of our lungs and whole process of singing generally.
Please have a look.
The mechanism of breathing
3D model of diaphragm
Diaphragmatic Breathing Technique