I have read here that the two major inhalation muscles are the (1) diaphragm and the (2) external intercostals.
Additionally, inhalation can also be caused by (1) expansion of the abdominal cavity, or (2) movement of the pelvic floor.
I thought that inhalation was caused by muscles that essentially cause the intra-thoracic pressure to drop, thus causing air to flow into the lungs to fill the absence, like a straw. This is what I thought caused us to inhale.
If my understanding is correct, then do the muscles cause this drop in pressure? Which spaces within the trunk experience this drop in pressure? If not, how exactly do these muscles facilitate inhalation?