Golfer's elbow (medial epicondylitis) is a breakdown of the tendons on the inner side of the elbow, where the forearm muscles that flex the wrist attach to the bone.

Tennis elbow (lateral epicondylitis) is a breakdown of the tendons on the outer side of the elbow, where the forearm muscles that extend the wrist attach to the bone.

The rotator cuff is a group of four muscles and tendons that stabilize the shoulder and control arm rotation. Rotator cuff tendinitis (or tendinopathy) is irritation and breakdown of these tendons from overuse, causing pain with overhead movement and at night.

Shoulder impingement syndrome occurs when the rotator cuff tendons and the bursa above them get pinched between the upper arm bone and the bony arch of the shoulder blade (the acromion) during arm movement.

The glenohumeral joint is the main ball-and-socket joint of the shoulder. When the cartilage lining this joint wears down, it causes deep shoulder pain and progressive stiffness.

Adhesive capsulitis, commonly called frozen shoulder, occurs when the capsule surrounding the shoulder joint becomes thickened, inflamed, and tight, causing progressive pain and a significant loss of motion, both when you move the arm yourself and when someone else moves it for you.