Why Pinched Nerves Cause Back and Neck Pain

Brain to the Spinal Cord and Beyond
Nerves extend from the brain into the arms and legs to send messages to the muscles or skin. A nerve that leaves the spine to go into the arms or legs is called a peripheral nerve. Peripheral nerves are bundles of millions of nerve fibers that leave the spinal cord and branch outward to other parts of the body such as muscles and skin. For example, these nerves make muscles move and enable skin sensation (feeling).

Nerves Carry Signals Throughout the Body
A peripheral nerve is like a fiber-optic cable, with many fibers encased in an outer sheath. You can think of each individual fiber as a microscopic garden hose. The green part of the hose is a fine membrane where a static electrical charge can travel to or from the brain. The inside of the hose transports fluid from the nerve cell body that helps nourish and replenish the ever-changing components of the green part, or membrane.

If the nerve is pinched, the flow up and down the inside of the hose is reduced or blocked, meaning nutrients stop flowing. Eventually, the membrane starts to lose its healthy ability to transmit tiny electrical charges and the nerve fiber may eventually die. When enough fibers stop working, a muscle may not contract and skin may feel numb.

What Causes a Pinched Nerve?
A nerve can be pinched as it leaves the spine by a herniated disc or bone spurs that form from spinal arthritis. Another common place for pinched nerves is the carpal tunnel. This is a bottleneck area, through which all the finger flexor tendons and the median nerve must pass to the hand. Regardless of where the nerve is pinched, in the neck or carpal tunnel, the patient often will feel similar symptoms of numbness in the hand, because the brain does not know how to tell the difference between the beginning, middle, or end of a nerve. It only knows that it is not receiving signals from the hand, and so numbness begins.

Nerve Structures

Symptoms of a Pinched Nerve
A pinched nerve in the low back usually is perceived as radiating down the leg. Here again, the symptoms the person experiences seem to be traveling into the leg along the usual path. This is the basis of referred pain. Muscle spasm in the back commonly accompanies pinched nerves and can be quite painful. Sometimes, nerves can be pinched and the only symptoms may be numbness and weakness in the arm or leg without pain.

Relieving Pinched Nerve Pain
A pinched nerve may be treated with medication, physical therapy, cortisone injection, or surgery. The goal of treatment includes:

• Reduce nerve inflammation by shrinking swollen tissue around the nerve
  
• Mobilize the nerve through scar tissue that may have built up around it (e.g., from chronic inflammation)
  
• Enlarge the nerve passageway
  
• Remove a disc and/ or bone spurs pressing on the nerve