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.
