The
vertebrae at the top of the
spinal column, composing the
cervical column, or
neck in animals that have a noticeable one.
Humans (and curiously, almost all other mammals) have seven of these vertebrae. In the human skeleton, they're the smallest vertebrae, denoted C1 through C7. Each has a foramen on either side for the vertebral artery to pass through.
The topmost vertebra is C1, commonly known as the atlas. It is followed by C2, the axis. C3 through C6 lack specific names; each has a short spine protruding backward which forks somewhat at its end. C7 is known as the vertebra prominens, having a longer, straight spine which is noticeable at the base of the neck.