What is a bone spur?
A bone spur (osteophyte) is a bony growth formed on normal bone. Most people think of something sharp when they think of a "spur," but a bone spur is just extra bone. It's usually smooth, but it can cause wear and tear or pain if it presses or rubs on other bones or soft tissues such as ligaments, tendons, or nerves in the body. Common places for bone spurs include the spine, shoulders, hands, hips, knees, and feet.
What causes bone spurs?
A bone spur forms as the body tries to repair itself by building extra bone. It typically forms in response to pressure, rubbing, or stress that continues over a long period of time.
Some bone spurs form as part of the aging process. As we age, the slippery tissue called cartilage that covers the ends of the bones within joints breaks down and eventually wears away (osteoarthritis). Also, the discs that provide cushioning between the bones of the spine may break down with age. Over time, this leads to pain and swelling and, in some cases, bone spurs forming along the edges of the joint. Bone spurs due to aging are especially common in the joints of the spine and feet.
Bone spurs also form in the feet in response to tight ligaments, to activities such as dancing and running that put stress on the feet, and to pressure from being overweight or from poorly fitting shoes. For example, the long ligament on the bottom of the foot (plantar fascia) can become stressed or tight and pull on the heel, causing the ligament to become inflamed (plantar fasciitis). As the bone tries to mend itself, a bone spur can form on the bottom of the heel (known as a "heel spur"). Pressure at the back of the heel from frequently wearing shoes that are too tight can cause a bone spur on the back of the heel. This is sometimes called a "pump bump," because it is often seen in women who wear high heels.
Another common site for bone spurs is the shoulder. Your shoulder joint is able to move in a number of directions due to its complex structure. Over time, the bones, muscles, tendons, and ligaments that make up your shoulder can wear against one another. The muscles that allow you to lift and rotate your arm (called the rotator cuff) start at your shoulder blade and are attached to your upper arm with tendons. As these tendons move through the narrow space between the top of your shoulder and your upper arm, they can rub on the bones. Bone spurs can form in this narrow area that, in turn, pinch the rotator cuff tendons, resulting in irritation, inflammation, stiffness, weakness, pain, and sometimes tearing of the tendon. This condition, rotator cuff disorder, commonly occurs with age and/or repetitive use of the shoulder. It is also common in athletes, especially baseball players, and in people such as painters who frequently work with their arms above their heads.