Leg Markings on Horses
Occasionally, you'll see white markings on the legs that the horse wasn't born with. These white marks are from old injuries. Because they are permanent, they too can be used as identifying marks.
Coronet
A coronet is a band of white hairs around the top of the hoof (the coronet band of the hoof) that does not extend up onto the pastern. If the coronet extends around the whole hoof, the hoof itself will likely be white. If there is a break in the white hairs where there is coat color, the hoof may have a dark stripe below it. If the white hairs only cover a small area just above the coronet band of the hoof, usually at the back the marking is called a heel or partial coronet.
Socks
Socks extend above the fetlock but not to the knee. Socks stop about half-way up to the canon bone on either the front or back legs. If the sock is solid white around the hoof, the hoof will most likely be white. If there is a patch of coat color or an ermine just above the hoof, there may be a stripe of dark hoof below.
Stockings
Stockings extend to the knee or hock and above. They may end in a symmetrical or pattern, or they may extend further up the leg in a jagged "irregular" pattern. If they extend well past the knee or hock they are called "high white."
Boot or Fetlock
A boot or fetlock is white that extends up to, but only slightly past the fetlock joint. A partial fetlock means that only a portion of the fetlock joint is covered with white hair.
Pastern
A pastern marking covers the pastern area but does not extend beyond the fetlock joint.
Ermines
Ermines are random black spots that appear on white areas on the horse's body. They can appear on the horse's white leg markings, and if they are against the coronet band of the hoof, there may be a stripe of dark hoof wall on an otherwise white hoof. Ermines can also appear on horse's facial markings.