Inside the elbow, in the area commonly called the "funny bone," the ulnar nerve runs under a bump of bone, the medial epicondyle. If this nerve, which is directly next to the bone and can be pressed against it, receives enough pressure, the way the nerve works can be disturbed. When this happens, numbness, tingling, and pain can be felt in the elbow, forearm, hand, and even all the way down to the fingers. This condition is known as cubital tunnel syndrome.
The pressure that disturbs the ulnar nerve can come from a variety of sources. The placement of the nerve, right next to the bone and lacking much padding, means that any pressure that is put on the bone is also felt by the nerve. You can sometimes glimpse this condition if you lean the inner part of your elbow against a table and feel your arm fall asleep. If the pressure is kept up, you may feel pain. If this happens repeatedly, the numbness and pain may last longer each time and can eventually become permanent. This is one of the potential causes of cubital tunnel syndrome.
In some people, the ulnar nerve may click as it goes back and forth over the bony bump when the elbow is bent and straightened back out. If this keeps happening, the nerve may become irritated. The ulnar nerve can also receive pressure if the elbow is bent for a long time and is stretched across the medial epicondyle; this can happen when sleeping. Sometimes the pressure comes from a thickening of the nerve's connective tissue or from differences in how the muscle over the nerve at the elbow is shaped. When the pressure on the nerve is large enough and keeps up for a long time, cubital tunnel syndrome can result.
If someone has cubital tunnel syndrome, they usually feel pain, numbness, or tingling in the ring and little fingers. The feelings are greater when the elbow is resting on an arm rest or when the elbow is repeatedly bent and straightened. The symptoms of cubital tunnel syndrome are often felt when the elbow is kept in the same position for a long time, such as when sleeping or holding a telephone.
Some people with cubital tunnel syndrome notice that their pinch is weaker or may occasionally be clumsy and drop things often. If the syndrome is bad enough, the hand muscles can lose size and strength and the numbness may become more extensive.
Cubital tunnel syndrome is determined by your hand doctor, who will check how your symptoms are distributed and what their pattern is. This involves checking the strength of your muscles and whether there is any loss of feeling. Your hand surgeon will also see how sensitive the ulnar nerve is to tapping or bending. You may also be checked for other medical conditions such as diabetes or any thyroid disease.
To confirm the diagnosis, you may be asked to have an electromyography (i.e., an EMG test) or a nerve conduction study (i.e., an NCS). These studies indicate the severity of your condition.
If the EMG/NCS tests show that the nerve isn't under a great deal of pressure, the symptoms of cubital tunnel syndrome can sometimes be reduced without surgery. The pressure on the nerve can be reduced by changing how the elbow is used. For example, you may be asked to refrain from resting your elbow on hard surfaces so as to ease your symptoms.
If the symptoms can't be reduced or eliminated and are too severe, a hand surgeon may suggest that surgery is the only method to eliminate the pressure. Sometimes the surgery involves shifting the ulnar nerve to the front of the elbow, and this treatment can reduce the pressure on the nerve as well as the tension it may be under. Other treatments involve placing a layer of fat under or inside the muscle and over the nerve or trimming the bony bump.
The process of recovery from surgery will depend on your particular course of treatment. Hand and wrist strength may take several months to return, and the numbness or tingling in the ring and little fingers may disappear quickly or slowly. If the cubital tunnel syndrome was extremely severe, the symptoms may continue, even after surgery.