C2 (cervical vertebra)
C2 is the symbol for the second cervical vertebra, which is also called the axis.
It is so-named because the uppermost cervical vertebra (called the atlas) rotates about the odontoid process of the second cervical vertebra.
The joint between the axis and atlas is a pivot type of joint.
It allows the head turn.</P> The Latin word 'axis' means axle or pole.
The axis bone serves as the axle about which the atlas (and the head) turn.