That is right, our dogs have shock absorbers just like vehicles and without these, the dog is in for a very bumpy ride. So where are these awesome parts on our dogs? I speak of the pasterns, of course.
All dogs have two sets of pasterns. Those familiar with anatomy may believe there are only the front pasterns, technically metacarpals, however, they would be mistaken. The rear pasterns a.k.a., the calcaneal process is the point of hock downward to the tarsal bones of the foot.
Briefly, the pasterns are the dogs’ shock absorbers for the body. Bear in mind that the forequarters are responsible for supporting more than half of the dog’s weight. Simply, no matter the gait, the heel of the dog’s lead foot will hit the ground first. This heel must consume the shock of impact. For these reasons, dogs’ feet have padded heels for softening impacts, these being the communal and digital pads. They also have a series of tendons and leverages in the feet and lower legs for pushing off. The latter is key in the rear pasterns, a.k.a. hocks.
So, why such a big deal over pasterns? The analogy of a vehicle is a good one to make because shock absorbers perform by offering resistance to movement. In other words, as the car drives over bumps, the shock absorbers compress as they absorb the forces and energy pressing down on them from the up and down movement taking place above. So it is the same with our dogs.
The metacarpal pasterns are energy absorbing mechanisms, and the rear pasterns or hocks are propellers. To propel, the muscles of the lower leg (below the stifle) connect to the tendons of the calcaneal process which in turn, when drawn, snap the rear pastern, foot, and digits, mobilizing the hindquarters. This is one aspect of the launching stage of the dog’s trunk and weight in a forward motion. The length of the calcaneal process will directly affect the function of the dog. A long calcaneal process is usually related to fast action, quick bursts of speed and is called ‘high in the hock.’ A shorter calcaneal process is typical of staying power for a dog who is not inclined to sprint, who has stamina. This is referred to as a low hock, or often described as ‘well let down in the hock.’ The functional difference is that a high hock, conducive to speed, produces and expends lots of energy while theoretically, a lower hock or shorter calcaneal process does not.
However, the devil is in the details as to the form of both sets of pasterns, and their form can make or break a working dog. When I use the term ‘working’, understand it is not exclusive to describing one of AKC’s Group classifications. The term references any dog that hunts, pulls, herds, retrieves, flushes and so forth.
The form of the pasterns is important because we have a variety of breeds and blueprints that require varying degrees of pastern shape. A galloping sighthound, such as the wolfhound, is to have well let down hocks with moderate length and slope of the front pastern. The length of the front metacarpal is important because if too long, the front feet flip up to avoid tripping. Compare this to the German Shepherd who has longer and more angled pasterns. Observing the footfall of the shepherd’s front feet depicts them nearly landing on the flattened pastern. The Shepherd’s ideal metacarpal is long, springy with a 25-degree angle from the vertical. The spring emanates from the length of the strong pastern because if it were short, the pastern would be stiff. An improperly formed pastern can affect this trotting dog’s considerable outreach as it is a part of his gait’s transmission. Typically, the longer the pastern, the longer the shape of the front foot. As an example, in a flying trot, you do not want to land on small, terrier feet.
On the other hand, the formation of a scent hound’s pastern, such as the beagle, is short and straight. This form aids the miniature foxhound while he casts for scent, back and forth with his nose forever to the ground. The American Foxhound has only very slightly, sloping metacarpals and if he were to have a pastern similar to the shepherd, he would be described as ‘down in the pastern.’ A serious fault for this breed’s architecture.
If you do not have good shock absorbers, the dogs will most likely be bouncing, up and down. This movement is typically faulty. Be careful not to misconstrue bouncing with springy which is elastic movement, resilient, limber with milliseconds of floating. This perceived floating is partly due to the pastern’s springing back. They rebound under the forces from above as they absorb the energy and then release it.
So, Mother Nature’s created the metacarpals and calcaneal processes for ‘damping’ movement. Resistance takes away energy and where there is energy, there is heat. I look forward to discussing energy, its release and how this translates to our dogs in another article.
This article first appeared on the Canine Chronicle website, Short URL: http://caninechronicle.com/?p=48199