The cervical spine consists of seven vertebrae, and they are the smallest of the spinal column. Together, the vertebrae support the skull, move the spine, and protect the spinal cord, a bundle of nerves connected to the brain.

All seven cervical vertebrae are numbered. The C1, the first vertebra in the column closest to the skull, is also known as the atlas, and the C2, the vertebra below it, is also known as the axis. The “C” stands for “cervical.”

 Many ligaments, or bands of connective tissue, wrap around the spinal column and connect its vertebrae. These ligaments also prevent excessive movement that could damage the spinal column.

Each vertebra has a protrusion on its backside called the spinous process. It extends backward and slightly downward. This is where ligaments and muscles attach to the vertebra.

Several muscles support the vertebrae of the spine. The spinalis moves the spine and helps maintain correct posture. It is divided into three parts:

• Spinalis cervicis: This muscle begins in the middle region of the spin and travel up to the axis. It may begin at the lower cervical vertebrae or the upper thoracic vertebrae. It helps extend the neck.
• Spinalis dorsi: This muscle begins at the upper thoracic vertebrae and extends down to the lower back.
• Spinalis capitis: This muscle is inseparably connected with another muscle in the neck, the semispinalis capitis.

The Longus colli muscle begins at the spinous process of the atlas at the top of the vertebral column and extends past the cervical spine to the third thoracic vertebra. This muscle is broad in the middle but narrow where it connects to vertebrae. It helps move and stabilize the neck.

The Longus colli is the most commonly injured muscle in car accidents when whiplash—the sudden jerking of the head at impact—occurs.