Why do I have neck pain?
There are many causes of neck pain. Doctors are not always able to pinpoint the source of a patient's pain. Your doctor will make every effort to ensure that your symptoms are not from a serious medical cause, such as cancer or a spinal infection. Below is a brief overview of some of the most common causes of neck pain.
Most neck problems happen after years of wear and tear on the parts of the cervical spine. At first, these small injuries are not painful. But over time they can add up. Eventually they begin to cause neck pain.
Doctors sometimes call these degenerative changes in the spine spondylosis. Spondylosis can affect the bones and soft tissues of the spine. However, it is important to know that most problems with spondylosis are a normal part of aging.
Degenerative Disc Disease
The normal aging process involves changes within the intervertebral discs. Repeated stresses and strains weaken the connective tissues that make up a disc. Over time, the nucleus in the center of the disc dries out. When this happens, it loses some of its ability to absorb shock. The annulus also weakens and develops small cracks and tears.
Often these changes are not painful. But larger tears that reach to the outer edge of the annulus can cause neck pain. The body tries to heal the cracks with scar tissue. But scar tissue is not as strong as the tissue it replaces. At some point the disc may finally lose its ability to absorb shock for the spine. Then forces from gravity and daily activities can take even more of a toll on the disc and other structures of the spine.
As the disc continues to degenerate, the space between the vertebrae becomes smaller. This compresses the facet joints along the back of the spinal column. As these joints are forced together, extra pressure builds on the articular cartilage on the surface of the facet joints. This extra pressure can damage the facet joints. Over time, this may lead to arthritis in the facet joints.
These degenerative changes in the disc, facet joints, and ligaments cause the spinal segment to become loose and unstable. The extra movement causes even more wear and tear on the spine. As a result, more and larger tears occur in the annulus.
The nucleus may push through the weakened and torn annulus and into the spinal canal. This is called a herniated or ruptured disc. The disc material that squeezes out can press against the spinal nerves. The disc also emits enzymes and chemicals that produce inflammation. The combination of pressure on the nerves and inflammation caused by the chemicals released from the disc cause pain.
As the degeneration continues, bone spurs develop around the facet joints and around the disc. No one knows exactly why these bone spurs develop. Most doctors think that bone spurs are the body's attempt to stop the extra motion between the spinal segment. These bone spurs can cause problems by pressing on the nerves of the spine where they pass through the neural foramina. This pressure around the irritated nerve roots can cause pain, numbness, and weakness in the neck, arms, and hands.
People with minor neck pain or stiffness are often told they have a muscle strain. However, unless there was a severe injury to the neck, the muscles probably haven't been pulled or injured. Instead, the problem may be coming from irritation or injury in other spine tissues, such as the disc or ligaments. When this happens, the neck muscles may go into spasm to help support and protect the sore area.
Mechanical Neck Pain
Mechanical neck pain is caused by wear and tear on the parts of the neck. It is similar in nature to a machine that begins to wear out. Mechanical pain usually starts from degenerative changes in the disc. As the disc starts to collapse, the space between the vertebrae narrows, and the facet joints may become inflamed. The pain is usually chronic. (Chronic pain builds over time and is long-lasting.) The pain is typically felt in the neck, but it may spread from the neck into the upper back or to the outside of the shoulder. Mechanical neck pain usually doesn't cause weakness or numbness in the arm or hand, because the problem is not from pressure on the spinal nerves.
Radiculopathy (Pinched Nerve)
Pressure or irritation in the nerves of the cervical spine can affect the nerves' electrical signals. The pressure or irritation can be felt as numbness on the skin, weakness in the muscles, or pain along the path of the nerve. Most people think of these symptoms as indications of a pinched nerve. Health care providers call this condition cervical radiculopathy.
Several conditions can cause radiculopathy. The most common are degeneration, disc herniation, and spinal instability.
Related Document: Vermont Sports Medicine Center Patient's Guide to Cervical Radiculopathy
- Degeneration: As the spine ages, several changes occur in the bones and soft tissues. The disc loses its water content and begins to collapse, causing the space between the vertebrae to narrow. The added pressure may irritate and inflame the facet joints, causing them to become enlarged. When this happens, the enlarged joints can press against the nerves going to the arm as they squeeze through the neural foramina. Degeneration can also cause bone spurs to develop. Bone spurs may put pressure on nerves and produce symptoms of cervical radiculopathy.
- Herniated Disc: Heavy, repetitive bending, twisting, and lifting can place extra pressure on the shock-absorbing nucleus of the disc. If great enough, this increased pressure can injure the annulus (the tough, outer ring of the disc). If the annulus ruptures or tears, the material in the nucleus can squeeze out of the disc. This is called a herniation. Although daily activities may cause the nucleus to press against the annulus, the body is normally able to withstand these pressures. However, as the annulus ages, it tends to crack and tear. It is repaired with scar tissue. Over time, the annulus becomes weakened, and the disc can more easily herniate through the damaged annulus.
If the herniated disc material presses against a nerve root it can cause pain, numbness, and weakness in the area the nerve supplies. This condition is called cervical radiculopathy (mentioned earlier). And any time the herniated nucleus contacts tissues outside the damaged annulus, it releases chemicals that cause inflammation and pain. If the nucleus herniates completely through the annulus, it may squeeze against the spinal cord. This causes a condition that is even more serious because it affects all the nerves of the spinal cord. This condition is called cervical myelopathy.
- Spinal Instability: Spinal instability means there is extra movement among the bones of the spine. Instability in the cervical spine can develop if the supporting ligaments have been stretched or torn from a severe injury to the head or neck. People with diseases that loosen their connective tissue may also have spinal instability. Spinal instability also includes conditions in which a vertebral body slips over the one just below it. When the vertebral body slips too far forward, the condition is called spondylolisthesis. Whatever the cause, extra movement in the bones of the spine can irritate or put pressure on the nerves of the neck, causing symptoms.
Spinal Stenosis (Cervical Myelopathy)
Stenosis means closed in. Spinal stenosis refers to a condition in which the spinal cord is closed in, or compressed, inside the tube of the spinal canal. Spinal stenosis may be caused by degenerative changes, such as bone spurs pushing against the spinal cord within the spinal canal.
However, stenosis can also develop when a person of any age has a disc herniation that pushes against the spinal canal. When the spinal cord is squeezed in the neck, doctors call the condition cervical myelopathy. This is an alarming condition that demands medical attention. Cervical myelopathy can cause problems with the bowels and bladder, change the way you walk, and affect your ability to use your fingers and hand.