When you bend your elbow, your ulnar nerve stretches several millimeters. While your elbow is bent, if you rotate your hand from the natural handshake position to palm down, such as when you use a computer keyboard or mouse, the ulnar nerve stretches more. Then moving your fingers up and down like when typing can further stretch and relax the nerve. Sometimes the nerve will shift or even snap over the bony medial epicondyle, a very painful event.

When you have to bend your elbows, rotate your hands, and move your fingers repeatedly in the workplace, as required for most computer programmers and modern office workers, the ulnar nerve can become inflamed and irritated over time. Constant irritation may result in scarring of the ligament over the cubital tunnel, trapping the nerve and causing additional problems. The result is cubital tunnel syndrome (CuTS).

Constant direct pressure on the elbow may also lead to CuTS. The nerve can be irritated from leaning on your elbow while you sit at a desk, drive a car or operate machinery. The ulnar nerve can also be damaged from a direct blow to the cubital tunnel.

The most common causes of cubital tunnel syndrome are:

• Using a computer
• Sleeping on bent elbows
• Repetitive factory work
• Long-distance driving
• Playing a guitar or other musical instrument