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I am Your Dog's Anterior Cruciate Ligament

Introducing Your Dog's Cruciate LigamentWhen Things Go Wrong

Not many people are aware that their dogs have cruciate ligaments. Dog owners often unexpectedly end up discovering this structure the very first time when they are at the vet because their dog is exhibiting rear leg limping that doesn't seem to be getting any better. This body part is often underestimated and lives mostly in the shadow, yet, it plays a very important role in a dog's ability to happily romp around. Today is dedicated to this fundamental structure which deserves more attention. So let's have the dog's cruciate ligament walk the red carpet today and put him on the spot of honor.

acl dog

Hello, it's your dog's cruciate ligament talking! Actually, to be correct, we are actually two: the "anterior cruciate ligament" (ACL) and the posterior cruciate ligament" which is also known as the caudal cruciate ligament (CCL). However, you'll hear vets talking about the anterior cruciate ligament much more because it's the ligament that is more likely to cause trouble. So in this article, me, the anterior cruciate ligament (yes, the troublemaker!) will do the most talking.

If you take a look at my name, you may notice how the word "cruciate" derives from the Latin word "cruciatus" which means "cross." The word ligament, on the other hand, derives from the Latin word "ligamentum" from ligare which means "to bind." What does this all tell you?

It tells you that I am a ligament made of fibrous tissue and that the term cruciate is used to refer to the fact that the anterior cruciate ligament and the posterior cruciate ligament criss-cross each other like the letter "X" as seen in the picture.

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I Am A Stabilizer

My main job is to connect one bone to another so to stabilize ('bind") an important joint--in this case, we're talking about the dog's knee joint to be exact. Both me and my fellow posterior cruciate ligament basically work as a team holding together the femur and the tibia which make up the dog's knee joint.

You hardly notice my hard work, but rest assured, I am very important! I basically keep your dog's tibia from slipping forward, while my fellow posterior cruciate ligament keeps the tibia from slipping backwards.

rottweiler cruciate ligament

When all goes well, I help stabilize your dog's knee joint so your dog can romp around happily without the tibia bone slipping forward and causing an abnormal range of motion, but sometimes accidents happen. How do I rupture in the first place? It's often an accident.

Your dog may have taken a bad step or his leg may have gotten caught in a hole. Dogs who are overweight may be more susceptible to me rupturing especially when they jump off a bed or truck. Large breed dogs are more likely to suffer from my rupture.

If I get torn, things start getting complicated. The knee no longer stabilized, develops an abnormal range of motion and the dog feels pain. Rear-leg limping is the most evident sign of trouble and dogs may engage in sloppy sits (sitting with both legs out to the side) and they may "toe touch" (keep only the tips of the toes in contact with the floor) when standing.

Dog owners may delay the vet visit assuming their dog just got a sprain, but it doesn't get any better after a few days. I am not a fast healing structure, and I can only heal in two ways: a long period of rest (conservative management) or an expensive surgery.

"Almost all dogs with ACL problems sit to the side, even when sitting for a treat. Sometimes the lameness comes on quickly but often it's a gradual progressive problem."~Colorado Canine Orthopedics and Rehab

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How does the vet test me to check if I am torn? There's a very specific test called the "drawer sign." The vet will basically move the dog's leg a certain way to see if the knee joint feels unstable. The vet basically feels the tibia bone slipping forward, which is the most distinctive sign when I am torn and no longer keeping things together. However, don't trust this test blindly, if your dog is tense or if the tear has been there for a while, the joint may appear stable, leading to a possible misdiagnosis.

For this reason, some vets will opt to have this test done under sedation. X-rays may help provide some hints to rule out bone cancer and check if any secondary arthritis may have set in, because you see, when I am no longer there to stabilize things, the dog's bones start slipping and rubbing against each other which can lead to arthritic changes down the road.

As seen, I am an important structure! What can dog owners do to prevent me from rupturing? Well, you can't really keep dogs in a safety bubble, but there are some things that may help. According to the American Kennel Club Canine Health Foundation, keeping your dog lean and active is a good way to help keep me in good shape as good muscle tone is important!

I hope this has helped you understand me better!

Kind regards,

Your Dog's ACL

Dog Pawprint


  • American Kennel Club Canine Health Foundation, Stabilizing the Stabilizer, retrieved from the web on Match 16th, 2016
  • Colorado Canine Orthopedics and Rehab, Clinical Signs of Canine ACL Tear, retrieved from the web on March 16th, 2016
  • Vet Specialists, Dog Cranial Cruciate Ligament Disease, retrieved from the web on March 16th, 2016

 Photo Credits:

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