Overview

A pinched nerve occurs when too much pressure is applied to a nerve by surrounding tissues, such as bones, cartilage, muscles or tendons. This pressure disrupts the nerve's function, causing pain, tingling, numbness or weakness.

A pinched nerve can occur at a number of sites in your body. A herniated disk in your lower spine, for example, may put pressure on a nerve root, causing pain that radiates down the back of your leg. Likewise, a pinched nerve in your wrist can lead to pain and numbness in your hand and fingers (carpal tunnel syndrome).

With rest and other conservative treatments, most people recover from a pinched nerve within a few days or weeks. Sometimes, surgery is needed to relieve pain from a pinched nerve.

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Symptoms

Pinched nerve signs and symptoms include:

• Numbness or decreased sensation in the area supplied by the nerve
• Sharp, aching or burning pain, which may radiate outward
• Tingling, pins and needles sensations (paresthesia)
• Muscle weakness in the affected area
• Frequent feeling that a foot or hand has "fallen asleep"

The problems related to a pinched nerve may be worse when you're sleeping.

When to see a doctor

See your doctor if the signs and symptoms of a pinched nerve last for several days and don't respond to self-care measures, such as rest and over-the-counter pain relievers.

Source: http://www.mayoclinic.com

Causes

A pinched nerve occurs when too much pressure (compression) is applied to a nerve by surrounding tissues.

In some cases, this tissue might be bone or cartilage, such as in the case of a herniated spinal disk that compresses a nerve root. In other cases, muscle or tendons may cause the condition.

In the case of carpal tunnel syndrome, a variety of tissues may be responsible for compression of the carpal tunnel's median nerve, including swollen tendon sheaths within the tunnel, enlarged bone that narrows the tunnel, or a thickened and degenerated ligament.

A number of conditions may cause tissue to compress a nerve or nerves, including:

• Injury
• Rheumatoid or wrist arthritis
• Stress from repetitive work
• Hobbies or sports activities
• Obesity

If a nerve is pinched for only a short time, there's usually no permanent damage. Once the pressure is relieved, nerve function returns to normal. However, if the pressure continues, chronic pain and permanent nerve damage can occur.

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Diagnosis

Your doctor will ask about your symptoms and conduct a physical examination.

If your doctor suspects a pinched nerve, you may undergo some tests. These tests may include:

• Nerve conduction study. This test measures electrical nerve impulses and functioning in your muscles and nerves through electrodes placed on your skin. The study measures the electrical impulses in your nerve signals when a small current passes through the nerve. Test results tell your doctor whether you have a damaged nerve.
• Electromyography (EMG). During an EMG, your doctor inserts a needle electrode through your skin into various muscles. The test evaluates the electrical activity of your muscles when they contract and when they're at rest. Test results tell your doctor if there is damage to the nerves leading to the muscle.
• Magnetic resonance imaging (MRI). This test uses a powerful magnetic field and radio waves to produce detailed views of your body in multiple planes. This test may be used if your doctor suspects you have nerve root compression.
• High-resolution ultrasound. Ultrasound uses high-frequency sound waves to produce images of structures within your body. It's helpful for diagnosing nerve compression syndromes, such as carpal tunnel syndrome.

Source: http://www.mayoclinic.com

Prevention

The following measures may help you prevent a pinched nerve:

• Maintain good positioning — don't cross your legs or lie in any one position for a long time.
• Incorporate strength and flexibility exercises into your regular exercise program.
• Limit repetitive activities and take frequent breaks when engaging in these activities.
• Maintain a healthy weight.

Risk factors

The following factors may increase your risk of experiencing a pinched nerve:

• Sex. Women are more likely to develop carpal tunnel syndrome, possibly due to having smaller carpal tunnels.
• Bone spurs. Trauma or a condition that causes bone thickening, such as osteoarthritis, can cause bone spurs. Bone spurs can stiffen the spine as well as narrow the space where your nerves travel, pinching nerves.
• Rheumatoid arthritis. Inflammation caused by rheumatoid arthritis can compress nerves, especially in your joints.
• Thyroid disease. People with thyroid disease are at higher risk of carpal tunnel syndrome.

Other risk factors include:

• Diabetes. People with diabetes are at higher risk of nerve compression.
• Overuse. Jobs or hobbies that require repetitive hand, wrist or shoulder movements, such as assembly line work, increase your likelihood of a pinched nerve.
• Obesity. Excess weight can add pressure to nerves.
• Pregnancy. Water and weight gain associated with pregnancy can swell nerve pathways, compressing your nerves.
• Prolonged bed rest. Long periods of lying down can increase the risk of nerve compression.

Source: http://www.mayoclinic.com