What is the origin of the idiom "in stitches" and when to use it?

The idiom "in stitches" originated from the world of medicine. In the past, "stitches" referred to the sutures used to close wounds or surgical incisions. When a person was said to be "in stitches," it meant they were laughing so hard that it felt as if they had burst their stitches or reopened a wound. Over time, the expression evolved to signify uncontrollable and hearty laughter, emphasizing the idea that something is incredibly funny.