Usually seen in middle aged to older dogs and occasionally also seen in cats.
Here is an Xray of the lumbar spine - the "small" of your back, with this dog lying on its side. We are interested in this dog's spine as it has been exibiting back pain.
1. This is a normal space between the vertebrae.
2 and 3 - these show extra bone growing below the vetebrae and these grow until they fuse with the vetebra adjacent and so the bone "bridges" the gap. When they fuse, there is no pain, just stiffness, but until they do, we see a pinching effect causing spike pains when the dog moves certain ways.
No quick cure for these and although one level may fuse, we often find other disc spaces becoming afected which cause ongoing problems.