The adam’s apple is also known as the throat Buddha because the bone shape looks like Buddha.
When prosperity wakes up it will push through whatever it's in and create a protuberance or bulge. Just imagine it pushing out of the wall, trying to get out, making a bulge. So prosperous!
This is a jukugo word that uses the on'yomi readings of the kanji. Here's a mnemonic for the reading of 起. To get out of this bulge, you use a key (き). The key lets you get out.