IRISH WOLFHOUND MOVEMENT & STRUCTURE
Wolfhound authority on shoulder layback, the 45 degree myth, and how bones fit the joints. 22 x-rays, photos of shoulder bone, joint function, and real dogs define angulation in most breeds.
Sighthound Shoulder Angulations
by Sue McClure
I'm often asked to explain my view on shoulders. It is easier to explain when I have the bones with me to demonstrate, but much harder to illustrate on paper. So please bear with me, as I try to get from point A to point B, in an attempt to illustrate as completely as I can.
The shoulder assembly is a complex interaction of bone, muscle, connective tissue, including tendons and ligaments. It all has to come together for the dog to have optimum front end movement, thought by many, including myself, to be the easiest to lose and the hardest to get back in breeding. The musculature is very complex and interactive, involving the spine, trunk and the shoulder assembly. Here, I will try to demonstrate how the skeletal configuration plays a part and why some things can and can't happen.
Many old books & writings refer to the shoulder of the dog as being, if proper, at a 45 degree angle of layback. More knowledgeable folks concur that this was erroneous, based on horsemen's observations, and not actual anatomy studies. We know that the horse and dog have different skeletal structure and movement, as well as purpose and size constraints. But there are still many who call for a 45 degree layback of the dog's shoulder.
I received a picture of my dog sent to me by someone trying to learn, with 90 degree angles super-imposed over him, asking if that wasn't a correct assessment. Not only is this particular dog very moderately angulated, but in that particular picture he was young, and young Irish Wolfhounds are straighter in angulation than they will be as adults. It was in trying to explain how shoulders work that I was moved to put this together and I share it for others.
What I have learned over the years is due to many mentors to whom we owe a debt of gratitude for their studies and willingness to teach. The most informative seminar I've attended on structure featured Bonnie Dalzell, who was a writer for the Windhound magazine before I contacted her about joining our panel, which included Connie Miller, with her take on the history of the dog.
Bonnie brought bones and stop action videos that made her explanations so simple to understand that I began collecting and studying bones myself, and for this illustration I use the skeletal remains of a 32 inch high, 7.5 year old wolfhound. The joint capsule, which keeps the joint lubricated and from grinding bone to bone is missing of course, and does have a part to play that is not illustrated here.
The first thing to understand is how the blade and the humerus fit and move together. It doesn't look like a straight, by the book, ball joint that has radial movement as does our own shoulder.
The canine doesn't have a clavicle, as do humans and birds that allows for the wider range of motion to the side. (It is helpful to envision yourself in a kneeling position corresponding to the dog on all fours. Because of your clavicle, you can not only move your arm forward and back, but you can raise it laterally, whereas the dog cannot.) The humerus has a good sized head on it and when you fit the scapula to it, you can see a groove that controls forward movement, but there is room for some play toward the back of the "ball" when the humerus is drawn back.
When you hold the two bones together (and the humerus is slightly longer than the scapula on sight hounds) in a position to where they are well seated, you do not get a 90 degree angle. In fact, at right angles, it is very apparent this would not be stable, when you add weight. Do understand that the musculature and ligaments are what ultimately hold the bones and joints in place. As noted, angulation in younger dogs is straighter than in older dogs. Young muscles and connective tissue are tight. As the dog ages, usage and weight, as well as exercise, or lack of it, play on the strength and flexibility of the organs and tissues that not only hold it together, but have an effect on the growth of the skeleton.
We might think the dog has a straight line formed from toe to top of the scapula, when in full extension, but as demonstrated in this picture of a borzoi in full stretch, this isn't so. The structure of the joint won't allow it.
The blade itself isn't connected to the spine and has room to slide back and forth with the joint as a moveable fulcrum, so that gives us a little more forward lift of the forelimb than just the joint alone, but in fact, the joint itself is limiting. (Because the shoulder isn't connected to the spine, muscles not only play a part in movement, but containment as well, however, I leave musculature for another author) First, let's examine real dogs in motion to see what I am talking about.
The dog on the left is on a different lead, but he has touched down with his left foreleg and you can see the give in the joints that accommodate the force of the landing. Imagine what a jarring the shoulder would take if the joint was at 180 degrees!
Here, the dog on the right, the angulation is playing more of a part in keeping the dog's joints from breaking down...it is not serving to move the dog forward. This is a very important observation. The dog is moving forward due to his momentum from the leap. This phase actually slows the dog down.
The general consensus is that reach equates to better movement, so why is the running dog not landing farther out? Because physics dictates that it doesn't need to. The dog is landing from a forward leap. The leg is keeping him from falling too far forward & downward, necessitating greater recovery time before he can again accelerate. The front leg is not going to contribute to moving the dog forward until his body weight is over the leg and he can begin to push off. Until that leg comes under the center of gravity, it is not moving the dog forward. If we understand that, then we can take another look at the shoulder angulation.
There are two things to observe in this ASFA pictured (left), as compared to the one on the right. First, where the rear legs are touching down, just behind the dog's keel and also, see how quickly the elbows have been drawn up from a very open angle as the dog pushed off into the suspension phase. This probably contributes to the lift the rear legs are about to give the body when they push it upward and forward into the leaping phase.
(Try a broad jump with your arms at your sides, and again using your arms to help the forward & upward movement)
There is no interference between rear legs and forelegs, as the rear legs come around the front legs. This makes it important not to be front heavy or too broad across the shoulder in comparison to the pelvic girdle. The legs spread outward at the stifle or knee joint to accommodate, but lets not go against the mechanics involved.d.
If we try to place the scapula where it forms a 90 degree angle, it rides on the back ball of the humerus, and would not be a stable joint. And how would it contribute to moving the dog efficiently? Theoretically, a more closed angle allows for more reach. We have already seen that forward reach is not as important as rearward thrust.
Below is a dog that appears quite angulated, with a very deep chest. In reality, the short neck belies part of the problem. The dog's elbows are well under this dog, but the tips of the blades are above the level of the spine, higher in the neck than they appear.
In the first photo, also note an indicator of loose connective tissue is in the flipping of the pads. I'm told that another is, that the dog's trunk is slung lower, giving him more apparent depth of chest, but his blades ride higher. As the dog aged, the instability of the shoulder became more evident, but this dog moves his legs in the correct planes. It's when he stands that he can "pop" his shoulder out. I use him to illustrate, not that angulation is bad, but that over-angulation in the shoulder of heavy dogs can lead to problems, and that not all causes of angulation are sound.
So it is important to understand the basic anatomy of the shoulder and not just look for more angles. This is also a good illustration of how age loosens the muscles and ligaments. Although front heavy and long, this was not an unattractive youngster, but his structure couldn't hold up.
While the dog on left is considerably larger than the one whose skeleton I use, placing the bones against the dog, might help one to visualize where they are in relation to the dogs body.
Note that the point of the shoulder is generally in line with the breast bone and the line of cartilage along the ribs.
In the black and white Wolfhound photo on the right I have superimposed the bones over a nicely angulated Irish Wolfhound.
They weren't shot at quite the same angle as the dog is standing but it is a good indicator of placement in a dog that has as much angulation as one would need in a sight hound.
Curtis Brown suggests that the sight hound doesn't need as much angulation in the shoulder as in the rear.
I end with a photo of Ch. Suntiger No Greater Love, displaying some of the many muscles involved in a truly functional sight hound front. I hope this presentation in TheDogPlace.org will help Sighthound enthusiasts and judges be able to visualize and better understand the purpose and structure of these exceptional breeds.
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