Tennis elbow is soreness or pain on the outside (lateral) side of the upper arm near the elbow.
Epitrochlear bursitis; Lateral epicondylitis; Epicondylitis - lateral
The part of the muscle that attaches to a bone is called a tendon. Some of the muscles in your forearm attach to the bone on the outside of your elbow.
When you use these muscles over and over again, small tears develop in the tendon. Over time, this leads to irritation and pain where the tendon is attached to the bone.
This injury is common in people who play a lot of tennis or other racquet sports, hence the name "tennis elbow." Backhand is the most common stroke to cause symptoms.
But any activity that involves repetitive twisting of the wrist (like using a screwdriver) can lead to this condition. Painters, plumbers, construction workers, cooks, and butchers are all more likely to develop tennis elbow.
This condition may also be due to constant computer keyboard and mouse use.