The cervical spine begins at the base of the skull and contains seven vertebrae and eight pairs of cervical nerves responsible for controlling the neck, arms, and upper body. The vertebrae are bony and stiff with no ability to bend. The main joint between two vertebrae is made up of a large spongy mass known as the disc. The discs can absorb downward forces placed on the vertebrae from the weight and movement of the head.
The discs are made up of an outer portion known as the annulus and a soft gel center known as the nucleus. The annulus keeps the nucleus contained. When trauma or degeneration causes the nucleus to be ejected through the annulus, it is referred to as a disc herniation. If the disc herniates in the direction of the spinal cord or nerve root, it may cause neurologic compromise. Disc herniations in the cervical spine can be serious and can, in some instances, cause paralysis. In most cases, patients complain of neck pain which radiates into one arm. The C5-C6 level represents 90% of cervical disc lesions.
In addition to disc herniation, neck injuries also take the form of vertebral dislocation, vertebral fracture, complete severance of the spinal cord, or compression of the spinal cord from a hematoma. Each year in America, approximately 11,500 significant spinal cord injuries occur. Approximately 6,500 people die of their injuries and 500 new quadriplegic and paraplegic patients are diagnosed.
In the United States, motor vehicle accidents account for approximately 37% of neck injuries with violent crime accounting for 26%, slip and fall-related injury accounting for 24% and the remaining 7% related to sports. Approximately 50% of vertebral fractures are to the cervical spine. Scientific studies have demonstrated that flexion/extension loads can cause the disc to fail as seen in a motor vehicle accident. MRI plays an important role in patients suspected of having disc injuries subsequent to whiplash. It can help determine the size, location and severity of the disc protrusion. However, an MRI may not be as effective in the early stages of this type of injury.
Some studies of spinal trauma have demonstrated a missed injury rate as high as 33%. In other words, physicians have missed the diagnosis of spinal injury in almost a third of the demonstrated spinal trauma cases. A delayed or missed diagnosis can be attributed to a failure to consider or suspect an injury to the cervical spine or to inadequate radiology or incorrect interpretation of that radiology.
Therefore, whether an injury causes only mild whiplash symptoms to the neck, a disc herniation, or injury to the spinal cord, it is important that the appropriate work-up and treatment regime be initiated and followed