Nerve

Pinched, trapped or damaged nerves can cause a range of symptoms in your hand or arm, including pain, numbness and weakness.

Most nerve conditions affecting the arm are quite easy to spot and treat. However, many other nerve problems require specialist examination and diagnostic testing.

It is not uncommon for these symptoms to be associated with a condition such as neck arthritis, whiplash or a shoulder problem.

However, the usual cause is a compression or injury to a nerve:

Carpal tunnel syndrome – this produces tingling, weakness or numbness in your hand, often noticed most at night. However, there are several variations of symptoms. It is the result of pressure on your median nerve as it runs through a narrow passage in the wrist called the carpal tunnel.

Usually it happens because the roof of the tunnel has become thickened and tight, but sometimes the contents of tunnel (mainly tendons) have become swollen and enlarged instead.

Often there is no reason identified for it to happen to you but it can be caused by repetitive hand motions, such as during manual work. It is also linked to pregnancy and certain conditions, such as diabetes, thyroid problems and arthritis.

Cubital tunnel syndrome – this occurs when the ulnar nerve becomes compressed or irritated on the medial (inner side) of the elbow. Here the nerve passes through a narrow space – the cubital tunnel – with very little soft tissue to protect it. Symptoms include pain over the forearm and elbow, tingling and numbness in the hand and fingers and clumsiness of the hand.

Nerve injuries – if you have had an accident and are now experiencing symptoms of agonising toothache-like pain, numbness and/or profound weakness then it is very likely that you have sustained a nerve injury. This can range from nerve bruising to complete severance of the nerve. More severe injuries mean that the nerve needs to re-grow. At best this will occur very slowly (only 1mm/per day). Your doctor will need to examine and test you regularly to make sure the recovery is occurring at the fastest rate possible and help manage your symptoms in the meantime.

Brachial neuritis – this is an unpleasant condition where one or more of the major nerves running from the neck to the arm stops working. It is believed to occur after a mild virus infection that you may not have even noticed. The symptoms experienced depend on the nerve affected. Most commonly it results in severe pain for a few months followed by extreme weakness of the shoulder and/or elbow as the pain subsides. It is not easy to diagnose and is probably much more common that we think. Examination and diagnostic testing by a specialist is the key.

Less common nerve entrapments – any nerve can be affected but the less common types can be hard to spot. Suprascapular nerve entrapment which can sometimes occur in sportspeople who make repeated overhead arm movements. The condition causes pain and weakness of the shoulder. Radial tunnel syndrome, which is caused by pressure on the radial nerve at the elbow is often confused with tennis elbow, resulting in a delay to treatment. It cannot be picked-up on nerve tests and is usually only diagnosed by a specialist with experience in the condition.

If your doctor suspects you may have nerve damage, you will likely be offered a nerve test. There are two main tests, which are normally conducted at the same time. However, detailed examination by your doctor is paramount as the results of nerve tests are not failsafe, they can sometime give a normal result even when there is nerve damage present.

• A nerve conduction test (NCS) uses small metal electrodes that are placed on the skin. These release tiny electric shocks to stimulate your nerves. They measure the speed and strength of the electric signals by the nerve.
• An electromyography (EMG) test involves inserting a very thin accunpuncture-type needle into the muscle. It measures contraction of the muscle after the nerve is stimulated.

Ultrasound and MRI scans are also sometimes occasionally recommended to assess the site of nerve injury or if the doctor suspects there is a structure compressing the nerve.