The cervical spine consists of seven vertebrae, the lower five of which are separated by five intervertebral discs. Intervertebral discs act as cushions and shock absorbers, but can wear out and degenerate over time. This process, called cervical degenerative disc disease, is commonly known as spinal osteoarthritis. According to the journal "Brain," 60 percent of people over age 40 have some degree of cervical disc degeneration. Early cervical disc disease may be asymptomatic, but as it progresses, it invariably causes a variety of symptoms.
Neck Pain and Stiffness
Cervical degenerative disc disease is generally thought of as a common result of aging, although neck injuries, poor posture, overuse, genetic predisposition and nutritional deficiencies can also cause the condition. As disc degeneration progresses, the neck can become less flexible and generate achy neck pain and stiffness, especially first thing in the morning or at the end of the day. According to the book "The Cervical and Thoracic Spine," degeneration of cervical discs accounts for 36 percent of all spinal intervertebral disc disease, second only to lumbar disc disease.
Reduced Neck Movement
As the cervical discs continue to degenerate and lose height, bone spurs, or osteophytes, typically grow from the vertebrae above and below the discs, causing noticeably reduced neck motion. Certain movements, such as neck rotation, can be reduced before movement in other directions is affected. With neck movement, a mild grinding feeling may also be noticed. In later stages of degenerative disc disease, global reduction of neck range of motion usually occurs, along with more audible “crunching” or “cracking” sounds.
Radiculopathy
With moderate to severe cervical degenerative disc disease, the reduced disc height and growing osteophytes can pinch or irritate the cervical nerve roots, which results in cervical radiculopathy, a type of nerve pain that causes burning, tingling and/or shooting pain into the neck, shoulders and arms--sometimes on one side, sometimes bilaterally. Radicular pain can also result from a lateral disc herniation, which can chemically irritate or injure the cervical nerve root. If injured, it could lead to more serious symptoms such as numbness, muscle weakness, loss of fine motor skills and reflex abnormalities.
Myelopathy
With severe cervical degenerative disc disease, disc bulges and herniations are more common. Disc bulges and herniations that occur in a posterior direction put pressure on the spinal cord; this is called central stenosis or cervical myelopathy. In fact, according to an article in the April 2010 issue of the journal "Spine," myelopathy is the most frequent cause of spinal cord dysfunction in individuals older than 55. Cervical myelopathy can cause numbness and muscle weakness in the neck, shoulders, arms, hands or even legs. With severe myelopathy, complete lack of reflexes and coordination, paralysis, and loss of bladder or bowel control can occur.
Headaches
At moderate to severe stages of cervical disc degeneration, nerves and spinal facet joints can become irritated, which can generate pain in the neck and into the back of the lower skull. The headache pain is usually dull and achy, but can become sharp with neck/head motion.
References
- "Brain"; Epidemiology of cervical radiculopathy: a population-based study from Rochester, Minnesota, 1976 through 1990; K. Radhakrishnan, et al.; April 1994
- "The Cervical and Thoracic Spine"; R.A. McKenzie; 1990
- "Spine"; Trends and variations in cervical spine surgery in the U.S.: Medicare beneficiaries 1992-2005; April 2009
- "Essential of Skeletal Radiology"; Terry Yochum, D.C.; 2002
- "Journal of Spinal Disorders"; Herniated Cervical Intervertebral Discs with Radiculopathy: An Outcome Study of Conservatively or Surgically Treated Patients; J.G. Heckmann, et al.; October 1999
