Under The Knife

The term "under the knife" is an idiom used for that of surgery. Surgery, scientifically, is a physical intervention on the human body, generally involving the cutting of tissue, hence the use of surgical knives. The earliest known usage of the phrase occurred in 1880. One its more common usages occurs when someone asks, "when are you scheduled to go under the knife?" in reference to an upcoming surgery.
There are those who believe that the phrase carries negative connotations. Rather than being informal, the use of the word "knife" in the phrase brings up connotations of a common butcher. However, others maintain that the euphemism is more akin to gallows humor, and that by bluntly addressing the negative aspects, one is in fact confronting a painful reality.
The phrase has entered into mainstream usage, serving as the title of a 1927 short story by H.G. Wells, a song by American punk band Rise Against, and EP by the band Hatebreed. It has also been used for the title of a video game, an episode of the TV show "Gotham" and countless journalism articles. It was also used as the title for documentary series by Louis Theroux, which examined the growing trend of plastic surgery in the United States. Given the elective nature of plastic surgery, the phrase "under the knife" has added connotations, referring not just to the general aspect of surgery, but the painful recovery process involved in cutting and reshaping human features.