They occur because osteoarthritis causes changes in the cartilage and bones of the affected joint.
As the joint gradually changes, the body may produce additional bone around it.
This extra bone can create the hard bump that becomes visible on the finger.
Why Do the Bumps Appear on Multiple Fingers?
Osteoarthritis can affect several joints at the same time.
If a person develops a Heberden’s node on one finger, similar changes may eventually appear on other fingers.
This does not mean that the bumps are spreading like an infection.
Instead,
