Calcaneal apophysitis is the technical name for what is more commonly known as Sever’s disease. It is a disorder of the growth plate (apophysis) at the back of the heel bone (calcaneus). This growth plate merges with the rest of the heel bone by the early teenage years, so it only can affect children up until that age. It is very common, especially in those children who are active.
The cause of calcaneal apophysitis is simply overuse. There is too much strain placed on the growth plate by the growing child so it becomes irritated. This is obviously common if they are more active, more likely to participate in sport on hard surfaces and if their calf muscles are tight.
The classic symptoms are pain at the back of the heel with increased activity and pain in the heel bone if it is squeezed from the sides. There are no changes that can be seen on x-ray or other imaging.