Bursitis is an infection, irritation, or inflammation of a bursa. The bursa is a small fluid-filled sac or cushion. There are many bursae throughout the body. They are found where a muscle or tendon slides across bone.
Bursae decrease friction between two moving surfaces. With aging, they can become paper thin. Then they no longer provide the necessary cushion. When the two body parts start to rub together, bursitis can occur. Sometimes repetitive motion causes the bursae to become inflamed.
The shoulder is a very complex joint with many moving parts, ligaments, tendons, and muscles. There is a fairly large bursa between the rotator cuff and the head of the humerus (upper arm bone). The rotator cuff is a group of four muscles and tendons that surround the shoulder joint.
An orthopedic surgeon can help diagnose the problem. A careful history and examination may pinpoint the exact cause of your painful symptoms. There is treatment available for bursitis, if that’s what’s causing your pain.