On the palm, the ulnar nerve passes under a ligament between two small wrist bones, the pisiform and hamate. The tunnel formed by the bones and ligaments is called Guyon’s canal. The Ulnar Nerve supplies sensation to the little finger and half of the ring finger. It is critical that the area of compression be localized to either the wrist (Guyon’s canal), or the elbow (cubital tunnel), or the neck (thoracic outlet syndrome, cervical radiculopathy) by physical examination and electrical studies prior to embarking on a treatment. All three may cause numbness and tingling in the same ring and small fingers.
What is a syndrome?
A syndrome is a set of symptoms and physical findings that point to a certain diagnosis. All the symptoms and physical findings are not always present.
Various symptoms and physical findings may be present in different grades of severity.
What is Guyon’s Canal syndrome?
Guyon’s Canal syndrome is numbness and tingling in the ring and small fingers caused by irritation of the ulnar nerve in the Guyon’s canal.
Symptoms
Symptoms begin with a feeling of pins and needles in ring and little finger. This is followed by decreased sensation and eventually weakness and clumsiness in the hand as the small muscles of the hand are involved.
What Causes Cubital Tunnel Syndrome?
Pressure on the ulnar nerve in the Guyon’s canal is usually caused by a cyst in the canal, clotting of the ulnar artery from repetitive trauma, or a fracture of the bony process called the hook of the hamate bone in a golfer’s from hitting the ground instead of the golf ball, or in a baseball player from heavy batting.
Treatment
A wrist splint may be worn to decrease the pins and needles sensation. If symptoms persist in spite of these treatment modalities, surgical decompression of the nerve is needed. This procedure involves cutting the ligament that stretches over the top of the ulnar nerve and forms the roof of Guyon’s canal.
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