Clean Run Magazine - December 2007 - 53

Withers Scapula (Shoulder Blade) C Prosternum D (Point of the Breastbone) Upper Arm (Humerus) important characteristics for a performance dog and are achieved, in part, through proper angulation. In addition to the major components of the rear assembly, also consider the feet, which, in several breeds, should be compact. Long thin toes are subject to injury when they get hung up on slats and various other perils in the canine performance world. prosternum (the point of the breastbone) should form a 45° angle with a line drawn from the withers to the prosternum (see angle “C” in the diagram). The shoulder blade (or scapula) is the bone between the prosternum and the withers; so when the angle is appropriate, the shoulder blade lays back toward the dog’s rear, as opposed to a more vertical position. The straighter the shoulder, the more vertical this bone will appear to lay. The bone from the prosternum to the elbow is called the upper arm (or humerus). The upper arm should also meet the same parallel line (through the rib cage to the prosternum) at a 45° angle (see angle “D” in the diagram). Thus, the front assembly is comprised of two 45° angles (angles “C” and “D”), which together form a 90° angle. It is important to note that full shoulder layback is not achieved until maturity; however, a good degree of layback and angulation should be evident in an eightweek-old puppy. One important thing to remember is that the length of the upper arm should equal the length of the shoulder. One should also note that when a dog is described as having “length of neck” this necessarily means that the dog has good shoulder layback, thereby having a greater number of vertebrae above the shoulder, rather than tucked under the withers. Editors’ Note: We would be remiss if we did not point out that there is a great deal of controversy regarding the feasibility of 45° shoulder angles in dogs. Radiographic evidence is showing that 30-36° is more realistic. Rather than engaging in that debate here, we would like to quote Pat Hastings from her book Tricks of the Trade, “…do not allow this controversy to become an excuse for not breeding the best you can. Remember, the straighter the shoulder, the shorter the reach.” Whether or not we agree on the existence of 45° shoulder angles, it is certainly a standard worth aspiring to. As seen in the diagram, the prosternum is an area where bones meet, angulation is required, and prominence is preferred. Many of the muscles powering the front end attach to the prosternum, and as such, a prominent prosternum should be evident even in a puppy. The prosternum should be an obvious extrusion easily felt when running your hands across the dog’s front. If a dog feels flat between the front legs and the neck then such a dog likely has an insufficient prosternum. 53 Front Assembly and Angulation At least as important as rear angulation is front-end angulation. Proper front assemblies are very important to the performance dog. The front end bears over half of the dog’s weight as he performs. With respect to jumping, a strong rear launches the dog, but the front end bears the majority of impact while landing. When ascending the A-frame, the front end takes the initial impact. The front assembly also bears significant impact in striding down and landing when performing the A-frame and the dogwalk. Unfortunately, nice front assemblies are a lot rarer than nice rear assemblies. To complicate matters further, dogs with very nice fronts do not reproduce them as readily as other virtues. Nevertheless, a better than average front should be a requirement for any serious agility contender. Overly “straight” fronts, as defined below, have caused many talented dogs to end promising careers early. There are several variables at play, all working together to create the front assembly. When evaluating the front of a performance prospect consider the extent of shoulder layback (placement of the shoulder blade or scapula). Locate the withers and analyze how far back these withers lay toward the rear of the dog. Withers that are situated farther up on the neck of a dog create a short-necked dog, a dog that is also straight in the front. Technically, a line drawn parallel to the ground through the rib cage to the © CLEAN RUN ground. Any disturbance in rear angulation will bring the back feet either too far up under the dog or too far out behind the dog. Thus, the hock will no longer set perpendicular to the ground. Technically, the rear angulation previously described is achieved when a line drawn perpendicular from the ground forms a 45° angle with the stifle bone (angle “A” in the diagram). In addition, the angle where the femur meets the pelvis bone should be 90° (see angle “B” in the diagram). This proper angulation allows the dog to propel himself by reaching up under his body with his rear legs. Technically, this aspect of movement is called “drive” as opposed to front-end movement where the dog “reaches,” extending his front end out before him. Good reach and drive are very December 07 | Clean Run
Clean Run Magazine - December 2007

Table of Contents for the Digital Edition of Clean Run Magazine - December 2007
