Can you crack your sternum?

[S0rath 0f the Black Sun]

Cracking knuckles, cartilage or joints are mostly just the popping a few air bubbles in your synovium or cartilage, it's not overtly hazardous but it becomes a habit and it may cause excessive wear and tear in your joints leading to breakdown of the same. To answer the question, yes I do crack my sternum often. I discovered it first year high in Aikido class when the instructor taught us some stretching exercises.