Back of neck
The vulnerable area at the base of the skull — the part of the body you cannot see and others can.
The back of the neck in a dream is the dream's image of a vulnerable area of the body the owner cannot see and everyone behind them can. The back of the neck is where touch is felt without being able to look at; it is also where blows traditionally land in a betrayal. The dream brings the back of the neck when something in your life — a piece of trust you have placed in what is behind you, an exposure to what is not in your direct view, a moment of being approached from behind — is currently being felt at the point of the body designed to register exactly that. A hand rested gently on the back of the neck by a trusted person is the dream affirming the safe approach. A chill at the back of the neck with nobody visible is the dream noting that the warning system is reading something your eyes have not yet found.