Many people have experienced a trapped nerve. The symptoms are usually pain down the arm or leg, depending on where the nerve is trapped, numbness or pins and needles and sometimes impaired sense of touch and occasionally a burning sensation. The discomfort can range from mild aching pain to severe and lancing.
Common Causes of Trapped Nerves
There are many places where nerves can become trapped but the usual areas are the neck region, the low back, elbow and wrist. Generally speaking, entrapment results from trauma to the area. This may be overt, such as a strain resulting from heavy lifting or due to micro-trauma from repeated overuse or misuse. Arthritis, which causes inflammation in and around joints, can lead to nerve impingement as can vertebral collapse seen in osteoporosis.
The nerves become trapped in areas where they run through narrow channels between tendons, muscles or bones. If the tissue surrounding the nerve becomes inflamed and swollen, it will impinge on the nerve. The nerve itself can become swollen from this pressure thus making matters worse. Infection can also cause nerve inflammation and swelling.
It's likely that for nerve impingement to cause pain, some inflammation has to occur. Simple pressure on a nerve causes numbness but not pain as any one who has slept heavily on an arm will know. So the pressure has the secondary effect of inflaming the nerve and producing pain.
Trapped Nerves in the Neck Region
Nerves in the neck arise from between the vertebrae and pass through the muscles of the neck and shoulder area to supply the skin, blood vessels and muscles of the arm and hand.
Nerve entrapment can occur at the vertebrae from bulging or ruptured discs, strained and or swollen tissue (this could be a muscle or ligament, either at the side of the spine or the shoulder and upper back area).
One common cause of micro-trauma is sitting for repeated long spells of time in front of a computer. In some people the combination of working (and therefore not being relaxed) and sitting still for long periods seems to cause a tension build up in certain muscle groups in the neck and upper back region.
Trapped Nerves in The Elbow and Wrist
The ulnar nerve at the elbow runs quite close the surface and so is prone to trauma. The reason the upper arm bone- the humerus - is called the funny bone is because of the "funny sensation" that arises from pressure on the ulnar nerve.
Compression of the nerve causes pain and numbness, and sometimes weakness in the arm and hand – mostly on the little finger side. The usual cause is trauma to the elbow or overuse of the forearm – unaccustomed DIY for example.
In the wrist the nerve that is most likely to become trapped is the median nerve. This passes through a narrow tunnel of tendons just before it branches into the hand.
The condition is known as carpal tunnel syndrome and causes pain, numbness, tingling and weakness in the hand - mainly the thumb side. Carpal tunnel syndrome can be caused by trauma and overuse but also by hormonal upset.
Trapped Nerves in The Lower Back
The causes of trapped nerves in the lower back are usually similar to those in the neck and may include disc problems or strained or swollen tissue tissue at the side of the spine or deep in the buttock region.
Entrapment can occur to the femoral or sciatic nerves but sciatic impingement is more common. The features are pain down the back the of the leg (usually only one leg), tingling, numbness in the toes or foot and sometimes weakness of the foot and lower leg muscles.
A serious variant of nerve impingement in the back occurs when the spinal cord itself, as opposed to the nerve roots coming from it, is affected. This is known as cauda equina syndrome and is usually due to a prolapsed disc which, instead of bulging to the side, protrudes into the spinal canal. This causes pain down both legs, numbness in the genital region and malfunction of the bowels and bladder. This is an extremely serious condition and requires urgent treatment – failure to do so can result in permanent loss of bladder and or bowel control and impairment of sexual function.
Consequences and Treatment of Trapped Nerves
Very often trapped nerves due to strained tissue or bulging discs will resolve without treatment. Underlying hormonal or inflammatory disorders need to be treated appropriately.
Numbness in the hands and feet, apart from being unpleasant, can result in injury to these areas being undetected resulting in more serious damage.
Muscles whose nerve supply is interrupted can become weak and wasted leading to possible impairment of the limb.
Treatments for trapped nerves include:
- Medication: Pain killers or anti-inflammatory drugs will help the pain but not the tingling or numbness.
- Manipulative therapy: This will quite often help relax tight tissue and increase spinal movement which can help free the nerve.
- Gentle exercise: This often has much the same effect as manipulation.
- Acupuncture: This may be able to dampen down inflammation.
- Injection of a long acting steroid into the area to reduce inflammation.
- Surgery: This is normally only resorted to when other treatments have failed and either the pain is unbearable or use of the limb is becoming impaired. The aim is to cut away tissue causing the impingement such as a disc or thickened tendon.
This article is for information only. If you have any health concerns you should consult your doctor.
Resources:
An Introduction to Neurosurgery by Jennett and Lindsay. Pub.Butterworth Heinemann 1994
Neurology: A Concise Clinical Text. Swash and Schwartz. Pub. Bailleire Tindall 1989
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