Base wide conformation positions the horse's hooves wider at the ground than the origin of its legs at the chest. This condition is seen in many narrow-chested horses and is usually accompanied by hooves that toe-out.
This condition causes more weight to be distributed on the inside of the horse's hoof, predisposing the horse to ringbone and sidebone. Horses that are base wide travel wide simply because their conformation forces them to do so.
See Relating Form to Function: Horse's Front Legs, Front View for more information.
