what is also known as the epistropheus?
In anatomy, the second cervical vertebra of the spine is named the axis or epistropheus. By the atlanto-axial joint, it forms the pivot upon which the first cervical vertebra, which carries the head, rotates. The most distinctive characteristic of this bone is the strong odontoid process known as the dens which rises perpendicularly from the upper surface of the body. That peculiar feature gives to the vertebra a rarely used third name: vertebra dentata. In some judicial hangings the odontoid pr