The cervical spine has 7 stacked bones called vertebrae, labeled C1 through C7. The top of the cervical spine connects to the skull, and the bottom connects to the upper back at about shoulder level. As viewed from the side, the cervical spine forms a lordotic curve by gently curving toward the front of the body and then back. This complex structure includes 7 small vertebrae, intervertebral discs to absorb shock, joints, the spinal cord, 8 nerve roots, vascular elements, 32 muscles, and ligaments.
The nerve roots stem from the spinal cord like tree branches through foramen in the vertebrae. Each nerve root transmits signals (nerve impulses) to and from the brain, shoulders, arms, and chest.
A vascular system of 4 arteries and veins run through the neck to circulate blood between the brain and the heart. Joints, muscles, and ligaments facilitate movement and serve to stabilize the structure. Neck mobility is matchless. It is capable of moving the head in many directions: 90° of flexion (forward motion), 90° of extension (backward motion), 180° of rotation (side to side), and almost 120° of tilt to either shoulder.