Cubital Tunnel Syndrome Symptoms and Causes

Cubital tunnel syndrome creates a sensation similar to the pain that occurs from hitting the "funny" bone in your elbow. The "funny" bone (ulnar nerve) crosses the inner (medial) side of the elbow and rests under a bump of bone called the medial epicondyle. The ulnar nerve begins in the side of the neck and ends in the fingers. Cubital tunnel syndrome is brought on by increased pressure on the ulnar nerve. When the pressure becomes severe enough to disturb the way the nerve works, you may experience numbness, tingling and pain in the elbow, forearm, hand, and fingers.

Cubital tunnel syndrome treatments range from changing the habits that caused the problem to cubital tunnel release surgery for the severest cases.

The multidisciplinary team of orthopaedic experts at North Shore-LIJ Orthopaedic Institute's Hand and Wrist Services in New York treats cubital tunnel syndrome as well as a broad range of conditions affecting the hand and wrist areas.

Cubital Tunnel Syndrome Symptoms

Cubital tunnel syndrome symptoms usually consist of numbness, tingling and pain in the affected area. You will most likely feel the numbness and tingling in your little and ring fingers. A few patients with cubital tunnel syndrome will have very little numbness, tingling or pain, but only notice weakness in the hand and/or shrinking (atrophy) of the muscles in the hand. These symptoms are usually felt when pressure is irritating the nerve, possibly when you are resting on your elbow or repetitively bending your elbow. Some people notice weakness while pinching or grasping which results in a tendency to drop things. In more severe cases, sensation may be lost completely and the muscles in your hand lose strength and shrink.

Cubital Tunnel Syndrome Risk Factors

Several risk factors may put you more at risk for developing cubital tunnel syndrome:

  • Prior fracture or dislocations of the elbow
  • Bone spurs or arthritis of the elbow
  • Swelling of the elbow joint
  • Cysts near the elbow joint
  • Repetitive or prolonged activities that require bending of the elbow

Cubital Tunnel Syndrome Causes

You can develop cubital tunnel syndrome in several ways:

  • Putting pressure on your elbow bone for too long – The bone the nerve sits next to has very little padding over it, so pressure on the bone will put pressure on the nerve. Putting pressure on the inner part of your elbow for an extended period of time can cause cubital tunnel syndrome and make your arm fall asleep as well as cause pain. If you make a habit of putting pressure on your elbow in this way (such as resting elbows on the desk while working on the computer), the numbness and pain may increase and become more persistent. Some patients experience a clicking of the nerve moving back and forth over the bony bump (medial epicondyle) as the elbow is bent and extended. The nerve will most likely become significantly irritated if this occurs repetitively over time.
  • Holding your elbow in a bent position for too long – This stretches the nerve over the bony bump and can create an increased amount of irritation. Positions like this can occur while you sleep or when you are on the phone for a long time. Eventually, this can cause cubital tunnel syndrome with the connective tissue over the nerve becoming thicker and affecting the nerve significantly.
  • Repetitive motions that can cause cubital tunnel syndrome – Motions like these naturally occur during pulling, reaching or lifting. That's why cubital tunnel syndrome is more common in occupations such as:
    • Assembly line workers
    • Checkout line workers
    • Data entry specialists or any job that requires extensive amounts of typing
    • Factory workers
    • Mechanics and others who operate vibrating tools
  • Prior elbow injuries or other injuries in the elbow area – These injuries cause local scar formation or deformation of the cubital tunnel which in turn compress on the ulnar nerve.
  • Many people who develop cubital tunnel syndrome have no clearcut activity or injury that can be identified as the actual cause of the condition. In these cases it is called idiopathic cubital tunnel syndrome. Often there is a tight band or an extra muscle pressing on the nerve at the inner side of the elbow that is the cause of symptoms. In these patients surgery to release the tight band or muscle relieves the pressure on the nerve and allows the nerve to recover and the symptoms to subside.
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