A golden retriever breeder's "moving x-rays" and the findings of an Afghan hound expert.
We examine additional research debunking the 45-degree shoulder angle theory.
The Debunking of the 45-degree Shoulder Angle Myth Continues.
A Golden retriever breeder and judge uses moving x-rays to study the movement of dogs
In the 1980’s, golden retriever breeder and judge Rachel Page Elliott decided she wanted to use cineradiography (essentially moving x-rays) to conduct her own study on dogs in motion. She had written the classic book “Dog Steps” in the 1970s to great critical acclaim but still pondered why so many people talked about a 45-degree shoulder blade angle.
In her quest to understand bone and joint motion in moving dogs, Elliott went to Harvard University’s Museum of Comparative Zoology. Using special equipment, numerous dogs of different breeds, type and conformation were photographed and x-rayed while moving on treadmills.
Still x-rays of the dogs were also taken while the dogs were standing naturally to assess the set of the shoulder.
Elliott came to the same conclusion as the other researchers mentioned above: the 45-degree shoulder blade layback is NOT appropriate for most breeds.
"Radiographic studies show that as a dog stands with the forelegs in a natural pose, a blade that sets about 30 degrees off a vertical plane--measured up the scapular ridge--is within normal limits for the average well-built dog." --Rachel Page Elliott, Dogsteps, A New Look
Our article on shoulder angulation continues below. Please scroll down to read more.
Rachel Page Elliott's Illustration on shoulder angulation and the effects on front leg extension.
Elliott argues a 45-degree shoulder layback would be a "mechanical impossibility to the dog's function."
In the diagram, "notice how the hypothetical 45 degree layback of the shoulder blade would set the shoulder joint in advance of the manubrium (forechest) where there would be no support of the ribs, and any upward swing would cause interference with cervical musculature." -- Rachel Page Elliott, DOGSTEPS: A New Look
Illustration from DOGSTEPS: A NEW LOOK, by Rachel Page Elliott, Third Edition, Doral Publishing, 2001.
Another book, authored by two long-time AKC breeder/judges, also disputes the 45-degree shoulder layback.
EDWARD GILBERT AND THELMA BROWN
Taking up where Curtis Brown and Rachel Page Elliott left off, AKC judge and sight hound breeder Edward M. Gilbert, Jr. and Thelma Brown co-authored one the best books on canine anatomy for the curious dog breeder/exhibitor.
In “K-9 Structure and Terminology”, the authors state about shoulder blades: “A 50 to 60 degree layback is well laid back.” This angle is measured from the point of the shoulder to a point on top of the shoulder blade. (NOT from the point of the breastbone to the top of the shoulder blade—the point of the shoulder and the point of the breastbone are not the same thing.)
For trotting dogs the “most efficient angle between the shoulder blade and upper arm for trotting is between 100 and 120 degrees,” Gilbert and Brown say. (The curly coated retriever standard calls for a 55 degree angled shoulder blade from the horizontal and the upper arm bone laid back at about the same degree. That angulation would result in angle between the blade and upper arm of 110 degrees, well within the "most efficient angle" range.)
Addressing the 45-degree angle mantra, the authors state: “While several breeds of dogs (standards) call for a layback of 45 degrees, 45 degrees is nonexistent in practically all breeds.”
" A 50 to 60 degree layback is well laid back." -- Edward M. Gilbert, Jr. & Thelma Brown, K-9 Structure and Terminology
Our article continues below. Scroll down to read more.
The book by Gilbert and Brown is an excellent one and should be in the library of every serious breeder and dog fancier.
One of aspects of judging shoulder angulation is the problem that most of us, because of muscling in the dog, cannot feel the ACTUAL angulation of the shoulder blade. To be an accurate measure, the angle must be measured from the bony process called the spine in the middle of the shoulder blade because that is where the muscles which move the shoulder and front assembly are attached.
Unfortunately, it is almost impossible to feel that shoulder spine so people end up measuring the angle from the top (sometimes called the point) of the shoulder blade to the point of the shoulder. (Or, in some cases people assess angle from the top of the shoulder to the manubrium (breastbone), which is NOT the correct measurement of shoulder and front assembly angles.)
"Well laid-back shoulder blades on a deep chest are considered best for dogs that move smoothly at a trot. The layback in a well laid-back shoulder is in the range of 60 to 50 degrees. This measurement is from the point of the shoulder to a point on top of the shoulder blade, as estimated in the show ring." --Gilbert and Brown, K-9 Structure and Terminology, Second Edition, 2001.
(Emphasis in the quote is mine.)
So, as you can see by the above quote, the 55-degree shoulder angulation as called for in the U.S. curly coated retriever standard is considered well within the range of a laid-back shoulder and correct for a long-legged, deep chested trotting dog.
Still Clinging to the Ol' 45-degree angle?
A modern-day team of German researchers use high tech to measure more than 300 dogs. And guessssss whaaaaaaat?
Related Articles to this one:
"While several breeds of dogs (standards) call for a layback of 45 degrees, 45 degrees is nonexistent in practically all breeds."
Gilbert & Brown, K-9 Structure and Terminology
There are several editions of the book written by Rachel Page Elliott. The one I discuss above is DOGSTEPS, A NEW LOOK. The NEW LOOK edition is the most up to date and is the one I discuss above.