Navicular syndrome has been cited as a common cause of forelimb lameness in horses. It is a condition where pain comes from the navicular bone at the back of the foot and the surrounding soft tissues.
Causes
Where the horse develops the wrong angles between the hoof and the foreleg, especially long toes and low heels, there is extra bio-mechanical strain is placed on the heel area. Conformation or poor farriery can therefore predispose the horse to developing navicular syndrome
Case study from Newmarket Equine Hospital