Ulnar nerve entrapment may also be called bicycler’s neuropathy or Guyon canal syndrome, depending on what part of the body the condition affects. It is the second most common nerve entrapment condition after carpal tunnel syndrome. Though similar, carpal tunnel syndrome affects the median nerve instead of the ulnar nerve.
The primary nerve in the arm, the ulnar nerve starts in the neck, runs through the shoulder, down into the arm, through the wrist, and into the fingers. It is one of the few nerves not protected by bone or muscle. Not only does the ulnar nerve provide sensation to the fourth and fifth fingers, but it also allows the muscles in the hand to flex and move. Because it runs through areas of the arm and hand that bend, the nerve can become compressed and cause a variety of physical symptoms ranging from slightly uncomfortable tingling or numbness to sharp, intense pain.
Compression of the ulnar nerve triggers ulnar nerve entrapment. The two most common sites at which this occurs are the wrist and the elbow, but it can also happen between the elbow and the shoulder or the elbow and the wrist. The ulnar nerve’s job is to transmit sensations and motor functions to the hand and the lower arm. If compressed as it passes through the wrist or elbow, the sensation transforms to tingling, weakness, or pain.
Activities that require repeated bending and straightening of the elbow, or any repetitive movements that cause stress injuries to the elbow, are common causes of ulnar nerve entrapment. The condition can also develop due to fluid buildup, arthritis, or swelling in the wrist joint or elbow. Bone spurs can cause entrapment, as can leaning on the elbow for extended periods of time, or sleeping with the arms folded. Fractures, dislocations, or direct trauma may contribute as well. Sports such as badminton or tennis, or work duties that require repetitive motions or excessive gripping, can also lead to ulnar nerve entrapment.
Because the ulnar nerve is a prominent nerve that runs from the neck down into the fingers, ulnar nerve entrapment causes a variety of symptoms throughout the length of the arm. Slight twinges may be felt when the elbow is bent, but issues most often occur in the fingers and wrist. Numbness and tingling are common, especially in the ring and pinky fingers, which may feel as though they are going to sleep. Weakness in the hand may make it difficult to grip or pick up items.
A tunnel of bone, muscle, and ligaments -- the cubital tunnel -- is located on the inside of the elbow. Fascia, a network of soft, connective tissue, covers the length. The ulnar nerve passes behind the medial epicondyle, a protective bone located at the elbow, before moving into the cubital tunnel. The “funny bone” is actually the ulnar nerve at the elbow. The sensation of hitting this sensitive area is similar to what people feel when they have cubital tunnel syndrome. Symptoms include numbness, tingling, aching pain, and weakness.
Although it is less common, ulnar nerve entrapment occurring at the wrist due to overuse is called Guyon’s canal syndrome. Generally, cyclists, weightlifters, construction workers, and others who are required to grip items for extended periods of time experience this version of the condition. Repeated twisting along with repeated hand and wrist movements exacerbate symptoms, and it may also occur following wrist or elbow trauma, or if there is a ganglion cyst at the wrist. Symptoms include muscle atrophy, numbness, pain, and weakness.
Women are more prone to ulnar nerve entrapment during pregnancy. Hormonal changes, edema, and other physical alterations occur in the nine months leading up to the birth of a child. The increased fluid buildup in the body during pregnancy puts more pressure on nerves, causing compression. The region of the ulnar nerve is most susceptible to nerve issues. The condition is usually temporary, however, and goes away shortly after the birth.
Ulnar nerve entrapment is not inherited, but some people are more prone to the condition, particularly those with a family history of compressed nerve issues. Generally, the prevalence of these conditions indicates genetic, physical growth that increases the chances of this compression. Hereditary neuropathy with liability to pressure palsies, or HNPP, is a hereditary disorder characterized by episodes of numbness and weakness that develop following even the slightest pressure or trauma to a single nerve. The most susceptible areas are the elbow and wrist.
Many treatments can ease the symptoms of nerve entrapment. Although most physicians do not recommend range-of-motion exercises, some stretching exercises may help naturally free the compressed nerve. However, resting the arm is also a crucial part of the recovery process. Many doctors prescribe anti-inflammatory drugs as well, to help ease any swelling and provide pain relief.
Some people deal with ulnar nerve compression and ulnar nerve entrapment throughout their lives. Sometimes, exercises do not help, and anti-inflammatory drugs do not relieve the pain. Over time, the chronic nature of such conditions could cause permanent nerve damage. In some cases, doctors may elect to perform surgery after non-surgical treatments have proven unsuccessful. The goal of surgery is to free the ulnar nerve, giving it room to move around, which increases blood flow and provides faster healing.
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