Cubital tunnel syndrome is a condition brought on by increased pressure on the ulnar nerve at the elbow.
What causes it?
Pressure on the ulnar nerve at the elbow can develop in several ways. The nerve is positioned right next to the bone and has very little padding over it, so the pressure on this can put pressure on the nerve. For example, if you lean your arm against the 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.