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The second vertebra at the top of the spinal column is usually referred to as C2 but it also has another name which reflects its function.
What is axis (cervical 2)? The second cervical vertebra is also called the axis, from the Latin "axis" and the Greek "axon", both meaning "axle". The axis (C2) has tooth-like projection, upon which the atlas (C1) fits and rotates, enabling us to turn our head. Most of the bones which make up the spine are named by using a letter (which reflects the region of the spine) and a number (which reflects its position within that region). The first two cervical vertebrae are the only individual bones of the spine which also have alternative names.