Knocked Out Without Wind

I’ve fallen, and I can get up, but I can’t breathe!
Whether it was because the school bully socked you in the stomach really hard, or you jumped off the garage roof with parachute made from a bath towel (don’t ask), you’ve probably have had “the wind knocked out of you” at least once. What is this exactly, and why is it so painful?
Medical types call this phenomenon a “diaphragm spasm.” The diaphragm is a large, dome-shaped muscle located underneath your lungs. When you inhale, you’re actually constricting the diaphragm, which draws the lungs down and expands the rib cage. This action creates a temporary vacuum, which is what pulls air through your nose and down to your lungs. When you exhale, the diaphragm relaxes and the lungs deflate.
If you receive a good, hard blow to the solar plexus, it can temporarily paralyze the diaphragm. This can also empty all the air out of your lungs (probably accompanied by an audible “Ooooof!”) and send your diaphragm into a spasm. While the diaphragm remains paralyzed, your lungs can’t inflate and you are unable to breathe. The nerves around that area are sending intense pain messages to your brain, but all you want to do is catch your breath. A momentary sense of panic ensues. Luckily, you usually recover in a few moments, but the sensation scary enough to keep most kids off the garage roof a second time.