Cervical Vertebrae

The spine is made up of three groups of bones called "vertebrae." The seven "cervical vertebrae" comprise the bony axis of the neck. Although these are the smallest of the vertebrae, their bone tissues are denser than those in any other region of the column. The transverse processes of the cervical vertebrae are distinctive because they have "transverse foramina", which serve as passageways for arteries leading to the brain. Also, the "spinous processes" of the second through the fifth cervical vertebrae are uniquely forked. These processes provide attachments for various muscles. Two of the cervical vertebrae are of special interest. The first vertebra ("atlas") supports and balances the head. It has practically no body or spine and appears as a bony ring with two transverse processes. On its upper surface, the atlas has two kidney-shaped facets that unite with the occipital condyles of the skull. The second vertebra is the "axis," which bears a tooth-like "odontoid process" on its body. This process projects upward and lies in the ring of the atlas. As the head is turned from side to side, the atlas pivots around the odontoid process.