A complicated system of ligaments and muscles serves to control movement, maintain posture, and support the head and neck. Ligaments are fibrous bands of soft tissue that attach bone to bone. The ligamentous system of the spine protects the intervertebral discs and spine from injury, and prevents excessive movement of the head and neck. The muscular system of the cervical spine is complex, and includes the deep erector spinae or paraspinal muscle groups that run parallel to the spine. In addition there are larger and more superficial muscles that help to move and protect the neck and head. When neck or spinal motion is pushed to the extreme, such as in a car accident or whiplash injury, these ligaments and muscles can be damaged. Ligament damage sprain and muscle damage strain can produce pain, soreness, loss of motion, and, if severe enough, joint instability. The term Cervical Sprain is used to describe the pain that sometimes occurs, following an acute injury to the soft tissue of the neck, including the ligaments, tendons and muscles. Irritation or injury of the structures of the spine may produce spasm and pain of the muscles of the head neck and shoulder area. Common muscles involved include the suboccipital muscles, trapezius, and sternocleidomastoid. Injury to the head and neck causing weakness or tightness of the muscles or laxity of the ligaments can result in pain, decreased ability to maintain good posture, limitation in movement and headaches.