Three types of twitch, all used to restrain a horse by exerting a clamping pressure on the upper lip. The twitch does not work by distracting the horse, as is sometimes thought, but instead causes the release of endorphins from the horse's brain, producing a calming effect. The twitch is considered a humane method of restraint and is commonly used by horsemen and veterinarians alike.

Photo by Bob Lemen. All rights reserved.