Cubital Tunnel Syndrome refers to the compression or irritation of the ulnar nerve as it crosses the inside edge of the elbow and the neurological symptoms that accompany it. Also known as ulnar nerve entrapment at the elbow, it can result in pain, swelling, weakness or clumsiness of the hand, and tingling or numbness of the ring and small fingers. Additionally, there may be pain and numbness on the inside of the elbow, the “funny bone” area.
The ulnar nerve is one of the three main nerves that serve the arm. It begins in the cervical (neck) area of the spinal cord and travels all the way down the arm into the hand. At the elbow the nerve runs through a small passage called the cubital tunnel. This area is located just under a bony bump on the inside of the elbow called the medial epicondyle. At this point the ulnar nerve sits quite close to the skin and is vulnerable to compression. Even a slight bump to the medial epicondyle can produce a one time shock-like feeling. This is commonly referred to as “hitting one’s funny bone.” In cubital tunnel syndrome the irritation or pressure on the ulnar nerve occurs in the same area of the elbow. However, it is more frequent and the symptoms are chronic.
The ulnar nerve provides sensation to the little finger and half of the ring finger. It innervates many of the small muscles of the hand as well as some of the bigger muscles of the forearm. The ulnar nerve also controls the muscle that pulls the thumb into the palm of the hand. When an individual has cubital tunnel syndrome they may experience a range of symptoms:
Numbness on the inside of the hand and in the ring and little fingers
Pain and tingling
Decline in ability to bring the thumb towards the little finger
Pain and numbness in the elbow
Muscle wasting of the hand
There are several risk factors that can predispose an individual to develop cubital tunnel syndrome. The condition can be the result of prior injury or trauma to the elbow, inflammation of the elbow joint, cysts, abnormal bone growth, or repetitive and prolonged activities involving the elbow. Actions that involve frequent bending of the elbow or constant pressure on the elbow (as in leaning on the elbow for long periods of time) are a common cause of cubital tunnel syndrome.
To diagnose cubital tunnel syndrome the doctor will first to a complete medical history. This will include questions about prior injuries to the elbow, work and home activities, as well as which parts of the hand and elbow are experiencing symptoms. A physical exam can include checking where the ulnar nerve is being pinched, what movements cause symptoms, as well as an assessment of feeling and muscle weakness in the hand and fingers. Further diagnostic tests such as imaging tests, nerve conduction, and muscle function studies may be ordered.
Many cases of cubital tunnel syndrome respond to conservative therapy. Measures such as avoiding or modifying actions that cause undue pressure on the elbow, bracing or splint to protect and to prevent over bending the elbow can be helpful, along with physical therapy and anti-inflammatory medications. Cases that do not show improvement and are severe may require surgery.