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Guyon's Canal

Ulnar tunnel syndrome, also known as Guyon's canal syndrome or Handlebar palsy, is caused by entrapment of the ulnar nerve in the Guyon canal as it passes through the wrist.  

Symptoms

 

Usually begins with a feeling of pins and needles in the ring and little fingers before progressing to a loss of sensation and/or impaired motor function of the hand muscles controlled by the ulnar nerve.

Causes

 

Ulnar tunnel syndrome is common in cyclists due to prolonged pressure of the Guyon's canal against bicycle handlebars. Another very common cause of sensory loss in the ring and pink finger is due to ulnar nerve entrapment at the Cubital Tunnel near the elbow, which is known as Cubital Tunnel Syndrome.  Some other causes of nerve entrapment include:

  

  • Osteoarthritis that cause pressure on the nerve

  • Tumors or ganglions in the wrist tissue

  • Enlargement of the bursa (fluid-filled sacs) in the wrist

  • Abnormalities in the muscles 

  • Fracture of the hamate, a bone in the wrist, or injury to wrist

  • Repetitive tasks with the hands, such as typing

  • Sports and vibrating tools

Treatment

If the condition is caused by a ganglion or cyst, these should be removed where possible. This surgery should provide relief from pain, numbness, weakness, or tingling. However, recovery from this type of surgery is slow and may take several months for the nerve to recover.

 

If a fracture is the culprit, surgery is usually required to remove any bone fragments to take pressure off the nerve.

Alternatively, a surgeon may cut a ligament to relieve the pressure in the wrist.

When repetitive strain causes ulnar tunnel syndrome, repetitive movements should be avoided where possible to avoid further irritation of the ulnar nerve. A wrist brace can also be worn to prevent the nerve from moving, allowing for healing time. Cyclists can wear padded gloves to take pressure off the nerve.