Tummy In, Tummy Out
The the lungs inhale and the stomach muscles tense, flattening or inverting the belly and exposing the bottom of the ribcage. This is the configuration you'll want to draw if your damsel is gasping, leaning backward, or trying on a corset. Note the heaving bosom!
The lungs exhale and the stomach muscles relax, making the belly protrude. We see less of the ribcage, and the belly button might be a bit reduced, if not smashed flat. This is the configuration you'll want to draw if she's sighing, leaning forward, or bellydancing! The bosom drops.
Posted by Paul Richards