What does the phrase his elevens are up mean regarding the process of dying?

Sailor: Pops ain't gonna be around long; his 'elevens' are up.

Goddard Bolt: What?

Sailor: His elevens! Look at the back of his neck. You see them two cords, stickin' out? They make, like, an 'eleven'. Once their up that's it. He's a goner.

It comes from the Mel Brooks movie "Life Stinks"