Age

• For some people, the cause of a bone spur is simply age. As you get older, you become more and more susceptible to their formation. This is partly due to the "wear and tear" the joints take from continued use. It stands to reason that joints in the body of someone who is older will have been used significantly more than those of a younger individual.
  
  

Overuse

• Bone spurs can be caused by overuse of a joint. The reason for this falls in line with age-initiated bone spurs. When someone overuses a joint, there is a greater potential for "wear and tear" that can result in an injury. If a joint is repetitively used (and misused), the connective tissue can become irritated and inflamed. Once this inflammation sets in, it can start to break down the cushioning material in the joint, sometimes to the point of bone-on-bone. To compensate for this, a bone spur will form.
  
  

Arthritis

• Another common cause of a bone spur is the condition of arthritis, which is wear and tear on the joints, causing loss of cartilage. A bone spur can form to offset this damage by trying to create new areas of bone.
  
  

Pressure

• Sometimes, a bone spur is caused by consistent pressure. When pressure is placed on a ligament, tendon or bone, the area can eventually become irritated and inflamed. To better illustrate this factor, just think about shoes. If you repeatedly wear shoes that are too tight, the back of your heel undergoes a great deal of pressure, irritating and inflaming the area. To counteract or lessen this irritation and inflammation, the body forms a bone spur, which releases some of the pressure being placed on those ligaments.
  
  

Weight

• Excess weight can cause a bone spur to form. In this situation, the excess weight causes the joints to bear more weight than they're equipped for as well as suffer a great deal more stress during impact when a person walks. As time goes by, a certain amount of compression can take place, prompting the body to compensate by forming a bone spur.