This is a true emergency and your veterinarian should be called immediately! Keep your horse calm, and do not allow him or her to walk with the nail in place. Do not remove the nail if your veterinarian can come promptly.
Radiographs taken with the nail in place are helpful to determine the path of the nail, and if the nail entered the bone or any synovial structures such as the coffin joint, navicular bursa, or digital tendon sheath. If any of these structures have been penetrated, surgical treatment and aggressive medical therapy may be necessary to treat infection, and prevent potential severe and life-threatening lameness that can result in founder of the opposite foot or even necessitate euthanasia.