Bone spurs, also known as Osteophytes, are bony projections that usually form along joints.
Bone spurs form due to the increase in a damaged joint's surface area. This is most commonly from the onset of arthritis. Bone spurs usually limit joint movement and typically cause pain.
Bone spurs form naturally on the back of the spine as a person ages and are a sign of degeneration in the spine. In this case the spurs are not the source of back pains, but instead are the common symptom of a deeper problem. However, bone spurs on the spine can impinge on nerves that leave the spine for other parts of the body. This impingement can cause pain in both upper and lower limbs and a numbness or tingling sensations in the hands and feet due to the nerves supplying sensation to their dermatomes.
Spurs can also appear on the feet, either along toes or the heel, as well as on the hands. In extreme cases bone spurs have grown along a person's entire skeletal structure: along the knees, hips, shoulders, ribs, arms and ankles. Such cases are only exhibited with multiple exostoses.
Osteophytes on the fingers or toes are known as Heberden's nodes (if on the DIP joint) or Bouchard's nodes (if on the PIP joints).
Bone spurs may also be the end result of certain disease processes. Osteomyelitis, a bone infection, may leave the adjacent bone with a spur formation. Charcot foot, the neuropathic breakdown of the feet seen primarily in diabetics, will also leave bone spurs which may then become symptomatic.