How do you get arthritis in the spine?

See below: We all eventually get some in our spines at some point from day to day living. If obese, have injury, will have more.

Everyones' spine : Ages leading to changes that are degenerative but may not lead to arthritic pain. There is an increased incidence of these changes in families where there is a genetic basis for this, in obese patients, in smokers and in some types of trauma to the spine. Even though all of us develop these changes, not all develop symptoms leading to the diagnosis of arthritis.

Aging: Is only part of the answer because so many factors influence it already mentioned: smoking, obesity, genetics, trauma. The overriding "reason" for arthrtitic spurs is that the body senses some type of instability in the spine and is trying to stabilize the area; the other type of arthritis is degeneration of the joint from overloading forces that erode the tissue more than you can repair.