The Importance of Good
Positioning
on Canine Hip X-rays
By Ed Frawley
I would like to thank Dr. Jane Brakken for help with my dogs and allowing me the use of her x-ray room to take these photos.
Hip Dysplasia (another article on the subject)
The positioning is so bad in this x-ray that the dog’s
owner should have refused to pay for it.
The purpose of this article is to teach the average dog owner how to determine if a hip x-ray is done properly on their dog’s hips. The article will demonstrate correct positioning and poor positioning. It will show 2 different sets of x-rays done on the same dog on the same day. One set has good positioning; the second set has poor positioning. You will see that with poor positioning, a dog’s hips can look worse than they actually are. You will also see that no matter what you do with positioning you can never make a bad hip into a good hip.
The photo of the hip x-ray above (labeled good positioning) was done on a 10 month old German Shepherd from my kennel. While the dog is slightly angled on the x-ray plate, the positioning for the hips is pretty good. The photo below (the same photo as above) shows the various points on an x-ray to look at to determine if the dog was positioned properly.
Good Positioning
Because this article is directed to the general public, I will not attempt to use the proper medical names for a lot of the terminology in this article.
The first thing to look at in an x-ray is to see if the legs come straight down from the hips with the knee caps square and looking alike. We don’t want to see one leg straight and the other going off at an angle.
The above photo has 3 sets of colored arrows (green, yellow and red).
The green arrows above point to the bone that the hip socket is built into. These bones almost look like wings. You will notice that you can see more of the wing on the right than the wing on the left. When the position is 100% perfect, both wings will look exactly alike.
The yellow arrows point to holes in the bone structure. When the body positioning is correct the 2 holes on the left side are the same shape and size as the holes on the right side. The positioning is good on this dog, but not 100% perfect. That’s why the holes on the right are slightly different than the left. This is most noticeable in the lower right hole being smaller than the left side lower hole.
The red arrows above are the first things I look at when examining an x-ray. They point to the amount of pelvis bone that is covered by the leg bones on the x-ray. If you look at the pelvis, you can see that with the legs fully extended straight down, the legs overlay the very corners or tips of the pelvis. You can see the overlap through the leg bone. The picture above shows an even amount of overlap on both sides of the pelvis.
The photo below shows a much larger overlap on the left of the screen than on the right of the screen. This is poor positioning.