One of the forums I frequent recently had a poster ask a question about the mechanics of breathing, so I made the following based on a model that was used in a grad school physiology lecture. However, that model was a professionally manufactured model. Hopefully it’ll give new providers that “Aha” moment when covering respiratory physiology. On a quick technical note, the last two ribs (11 and 12) move in a “caliper motion,” which is simply out and in, unlike pump handle or bucket handle ribs.