Cervical Radiculopathy (“Pinched Nerve”)
Nerve roots that go from the spinal cord in the cervical spine travel into the arm. Along the way, these nerves supply sensation (feeling) to areas of the skin from the shoulder to the fingers. They also carry electrical signals to muscles that move the arm, hand, or fingers. Problems occur when one of these nerves becomes inflamed and is pinched by a herniated disc or bone spur. This may show up as weakness, numbness, and pain where the nerve travels. The pain may feel deep, dull, and achy. Or you may have sharp, shooting pain along the path of the nerve. Muscles controlled by the affected nerve root may also weaken. In the neck, this condition is called cervical radiculopathy.
The neck is subject to tension and pressure when the neck moves. The disc between each vertebra responds by acting as a shock absorber. Bending the neck forward compresses the discs between the vertebrae and tends to bulge the discs backward toward the spinal canal and nerve roots.
Problems may occur when the center part of the disc, the nucleus pulposus, squeezes out of the disc and puts pressure on nerves in the neck. This condition, called disc herniation, can happen when a tear in the outer ring of the disc (the annulus) allows the nucleus to squeeze through. The annulus can tear or rupture anywhere around the disc. If it tears next to the spinal canal, the nucleus can squeeze out and put pressure on the spinal cord or spinal nerves. Pressure against the nerve root from a herniated disc can cause numbness and weakness along the nerve. When the nerve root is inflamed, the added pressure from the disc may also cause vague, deep pain in the neck, shoulder, and upper arm. It can also cause sharp, shooting pain to radiate along the pathway of the nerve.
This condition may occur when too much force is exerted on an otherwise healthy intervertebral disc. Heavy forces on the neck may simply be too much for even a healthy disc to absorb.
Herniated discs are more common in middle-aged adults. This is because the natural process of aging causes the discs to become weakened from degeneration. Less force is needed to cause the degenerated disc to herniate. Not everyone with a herniated disc has degenerative problems. Likewise, not everyone with degeneration will suffer a herniated disc.
In older people, degenerative disc disease can cause bone spurs to form near the nerve roots. If these bone spurs get big enough, they may begin to rub on the nerve root and irritate it. This usually occurs inside the foraminae, which are small openings on each side of the spinal column where the nerve roots leave the spine. An irritated nerve root that is squeezed by a bone spur can cause the same symptoms as a herniated disc in the neck-pain, numbness, and weakness in the arm.