The pastern is the stretch of bone between the hoof and the fetlock. On a human, the pastern is equivalent to the long phalanges of the hand (bones of finger from knuckle to fingertip).
Because of its singular nature as a word, some might believe the pastern is one bone. However, the pastern is technically made up of three bones and two joints: the long pastern bone, from fetlock joint to top of hoof (or coronary band); the short pastern bone, from coronary band to the coffin bone; and the coffin bone itself.
The pastern functions as a shock absorber, and endures thousands of pounds of pressure over the course of a horse’s life. It also serves as the location where suspensory ligaments and flexor tendons attach to muscle.
An ideal pastern slopes at a 45 degree angle in the front leg, 50-55 degree angle in the back leg, and is relatively smooth, free of scars or bumps. It flexes naturally in concert with the upper and lower joints of the leg, however, is rigid in nature. There is no swelling on either side, front or back. A "club-foot" is a poorly angled pastern, one that is quite upright, and can cause lameness problems down the road.
However, as with human ankles – no two of which are identical - some differences in pastern appearance may occur from horse to horse, not all of which differences necessarily indicate injury or lameness. Therefore, it is a good idea to regularly examine each of your horse’s pasterns to become familiar with any peculiarities that might be present. Determine also whether the angle on your horse’s pasterns make the horse suitable for the type of event in which you wish to participate. For example, a club-footed horse might be able to live a pain and injury free life with care from its owner, however, would never be able to compete in agility events.
Pastern Injury
Definite times to call out the vet include:
• Inflamed scars or other unexplained redness
• Deep wounds
• Area is hot to the touch
• Bulging under the skin, especially if soft or squishy (which indicates a fresh sprain)
• Bony protuberances at any of the pastern joints
Hard bulges generally indicate scar tissue from an old injury. While equally important to evaluate, if the older injury is not hot to the touch and does not appear to cause the horse pain, have it checked during a regular vet visit. Some injuries, such as ringbone, if treated early, have good prognoses, depending on which joint is affected.
Maintaining Healthy Pasterns
In addition to regularly inspecting the pasterns, hooves and fetlocks, take steps to prevent injury. To guard against abrasions, use padded leg wraps during loading, trailering, and any other situation where the horse might get stepped on by another horse or will be in tight quarters.
Overreach boots for the front hooves work well in preventing clipping abrasions, and can be used during all types of riding. Pastern wraps function in the same way. (Note: Leg wraps of any kind should not be left on for lengthy periods of time.)
Remove debris such as wire, bailing twine, loose boards, and protruding metal in stalls. Level out potholes or depressions in fields and pastures to prevent stumbling. Small animals can create new burrows and holes overnight, so check the pasture frequently.
Horses used in sports that place heavy demands on the pastern - such as barrel racing, cow cutting, or jumping - should receive additional periods of rest between workouts to let the tendons and joints at the pastern recuperate.
Poorly-angled hooves can irritate the pastern joints, therefore, make sure the farrier is shaping your horse’s hooves correctly.
By taking these precautions and regularly inspecting and getting to know your horse's pasterns, an owner can quickly spot irregularities and injury. Prevention is best; however, rapid treatment can make a world of difference to a horse's future.
