What is the lump on my horses belly?

My pony has a lump on his tendon?

• My 16 month old dartmoor pony has a lump on his back tendons. On one leg it is one BIG lump which is just about see able from eye site and on his other leg he has two small ones that i can feel. Neither of them are causing him any pain. (from what we can see) there is no swelling, it's not hot. it's not nothing really. just this lump which won't go away. We've been trying to soak it with the hose each day but hes still learning to except the hose. So he can make it very difficult sometimes. He is turned out with his two friends. A 31inch shetland colt and a 15.1 8year old mare. him and the colt are always running aroud and playing and on occasion him and the mare do to. theres only the 3 horses on the yard and he hates being alone. He also has a straight cut along his left back heel. I have checked his field and theres nothing he could of caught it on. Any ideas?

• Answer:

  They sound like splints. A horse splint is a bony growth that can be found on the splint bones of the horses lower leg. Splints can occur when the interosseous ligament becomes damaged, and in some cases lead to soft tissue inflammation and lameness with heat, pain and swelling in the area between the splint bone and cannon bones. As any inflammation settles and healing proceeds, new bone is laid down in this area, eventually forming a hard, non-painful lump, the size of which depends on the degree of original damage. This is the splint, which will reduce in size over time, but is unlikely to disappear. The new bone stabilises the source of irritation by forming a bridge between the digits. These splints occur most typically on the inside of the forelimb, or on the outside of the hind limb in young, immature horses in work. Poor conformation, mineral imbalance in the diet, excessive weight of horse or rider, work on hard and uneven going, and unbalanced hooves can all lead to splints forming. The splints could have been caused if he was running about like youngsters do hen the ground was especially hard in the summer and then the bony umps have formed now the actual true splint has healed.