Cervical radiculopathy, commonly called a "pinched nerve" occurs when a nerve in the neck is compressed or irritated where it branches away from the spinal cord. This may cause pain that radiates into the shoulder, as well as muscle weakness and numbness that travels down the arm and into the hand.

CAUSE

Cervical radiculopathy most often arises from degenerative changes that occur in the spine as we age or from an injury that causes a herniated, or bulging, intervertebral disk.

• Degenerative changes-As the disks in the spine age, they lose height and begin to bulge. They also lose water content, begin to dry out, and become stiffer. This problem causes settling, or collapse, of the disk spaces and loss of disk space height.
• Herniated disk. A disk herniates when its jelly-like center (nucleus) pushes against its outer ring (annulus). If the disk is very worn or injured, the nucleus may squeeze all the way through. When the herniated disk bulges out toward the spinal canal, it puts pressure on the sensitive nerve root, causing pain and weakness in the area the nerve supplies.

Most of the time cervical radiculopathy appears unilaterally, however it is possible for bilateral symptoms to be present if severe bony spurs are present at one level, impinging/irritating the nerve root on both sides. If peripheral radiation of pain, weakness or pins and needle are present, the location of the pain will follow back to the concerned affected nerve root.

When disc herniation leads to compression of only an exiting nerve, this condition is referred to as radiculopathy. When disc herniation leads to compression of the spinal cord, this compression may lead to a group of symptoms referred to as myelopathy. Sometimes both the exiting nerves and spinal cord are affected, leading to a condition referred to as myeloradiculopathy. 

Cervical radiculopathy is a dysfunction of a nerve root in the cervical spine, is a broad disorder with several mechanisms of pathology and it can affect people of any age, with peak prominence between the ages of 40-50. Reported prevalence is of 83 people per 100,000 people. Annual incidence has been reported to be 107,3 per 100.000 for men and 63,5 per 100.000 for women

The most common level of root compression is C7 (reported percentages 46.3–69%), followed by C6 (19–17.6%); compression of roots C5 (2–6.6%) and C8 (10– 6.2%) are less frequent. One possible explanation is that intervertebral foramina are largest in the upper cervical region and progressively decrease in size in the middle and lower cervical areas, with an exception of the C7-Th1 foramen (C8)