What they are:

Scars can form lumps and bumps anywhere on your horse’s body. A scar forms when an injury heals but some disorganised tissue remains. Scars that occur across bones are especially noticeable. Scars typically feel somewhat hard, and perhaps stringy. In most cases, they are not sensitive to touch or pressure.

Treatment: 

It is important that you know your horse’s scars. Old scars rarely cause problems, but if you see anything that concerns you and you didn’t see the original injury to explain it, call your vet.