Bone spurs, also known as osteophytes, are bony projections that form along joints and are often seen in conditions such as arthritis. The bone spurs themselves aren\'t painful, but they can rub against nearby nerves and cause pain. 
Bone spurs are largely responsible for limitations in joint motion. The reason for bone spur formation is the body’s attempt to increase the surface area of a joint to better distribute weight across a joint surface that has been damaged by arthritis or other conditions. Unfortunately, this is largely wasted effort by our body as the bone spur can become restrictive and painful. 
Bone spurs are a signal of an underlying problem that often needs to be addressed. It isn\'t clear what causes bone spurs, but doctors believe they occur in reaction to changes in your joints due to diseases and aging — most commonly osteoarthritis.