The cervical spine is made up of the first seven vertebrae in the spine. It starts just below the skull and ends just above the thoracic spine. The cervical spine has a lordotic curve, a backward "C"-shape-just like the lumbar spine. The cervical spine is much more mobile than both of the other spinal regions. Think about all the directions and angles you can turn your neck.
Unlike the rest of the spine, there are openings on each side of the vertebra in the cervical spine for arteries (blood vessels that carry blood away from the heart). The arteries that run through these openings carry blood to the brain.
The upper two vertebrae in the cervical spine, the atlas and the axis, differ from the other vertebrae because they are designed specifically for rotation. These two vertebrae are the reason your neck can move in so many directions.
The atlas is the first cervical vertebra-the one that sits between the skull and the rest of the spine. The atlas does not have a vertebral body, but it does have a thick forward (anterior) arch and a thin back (posterior) arch with two prominent sideways masses.
The atlas sits on top of the second cervical vertebra, the axis. The axis has a bony peg called the odontoid process, which sticks up through the hole in the atlas. It is this special arrangement that allows the head to turn from side to side as far as it can. Special ligaments between the atlas and the axis allow for a great deal of rotation.
The cervical spine is very flexible, but it is also at risk for injury from strong, sudden movements, such as whiplash-type injuries. There is limited muscle support in the cervical area. The head weighs about 12 to 15 pounds and is balanced on top of the atlas bone at the top of the spine. Sudden, strong head movements can cause damage to the bones, ligaments, or even the arteries that carry blood to the brain.