Cubital Tunnel Syndrome
Cubital tunnel syndrome is a condition brought on by increased pressure on the ulnar nerve at the elbow. There is a bump of bone on the inner portion of the elbow (medial epicondyle) under which the ulnar nerve passes. This site is commonly called the “funny bone” (see Figure 1). At this site, the ulnar nerve lies directly next to the bone and is susceptible to pressure. When the pressure on the nerve becomes great enough to disturb the way the nerve works, then numbness, tingling, and pain may be felt in the elbow, forearm, hand, and/or fingers.
Cubital Tunnel Syndrome Causes
Pressure on the ulnar nerve at the elbow can develop in several ways. The ulnar nerve is positioned right next to the bone and has very little padding over it, so pressure on this can put pressure on the nerve. For example, if you lean your arm against a table on the inner part of the elbow, your arm may fall asleep and be painful from sustained pressure on the ulnar nerve. If this occurs repetitively, the numbness and pain may be more persistent. In some patients, the ulnar nerve at the elbow clicks back and forth over the bony bump (medial epicondyle) as the elbow is bent and straightened. If this occurs repetitively, the nerve may be significantly irritated. Additionally, pressure on the ulnar nerve can occur from holding the elbow in a bent position for a long time, which stretches the nerve across the medial epicondyle. Such sustained bending of the elbow may tend to occur during sleep. Sometimes the connective tissue over the nerve becomes thicker, or there may be variations of the muscle structure over the nerve at the elbow that cause pressure on the nerve. Cubital tunnel syndrome occurs when the pressure on the nerve is significant enough, and sustained enough, to disturb the way the ulnar nerve works.