What’s the Difference between the Cranial Cruciate Ligament and the Anterior Cruciate Ligament?

Dr. Debra,

My dog has been limping on his right rear leg all weekend. It started Saturday after he was running in the yard. I took him to the vet, who said that my dog’s knee was swollen and that he had ruptured his anterior cruciate ligament (ACL). I’ve been doing some reading and the only information I can see is on the cranial cruciate ligament.

Are they the same? What’s the difference between the cranial cruciate ligament and the anterior cruciate ligament in dogs?

Virginia B., Jefferson City, MO

Hi Virginia,

Thanks for your excellent question. I’m sorry to hear about your dog’s knee problem; I hope he is doing okay now.

To answer your question, the cranial cruciate ligament and the anterior cruciate ligament refer to the same body part, and the terms are used interchangeably.

There are two cruciate ligaments in the canine knee: the cranial (anterior or front) and the caudal (posterior or back). They are located in the knee joint and work to form an “X” pattern that connects the femur (upper leg bone) with the tibia (the biggest of the two lower leg bones). The function of the ACL is to stabilize the tibia and prevent twisting and over-extension of the joint.
The anterior (cranial) cruciate ligament is often abbreviated and referred to by the letters “CCL” or “ACL.” When human injuries are involved, people tend to use “ACL” more frequently; you often hear the term in reference to injuries to athletes such as football players.

A cruciate ligament tear, also called a cruciate ligament rupture, is a rip or tear of one of these two important pieces of tissue. The tear can be complete or partial and can occur in one or both knees. Tears in the ACL/CCL are the most common ligament injury in dogs, and it most often occurs to larger breed dogs. For more information, go to our Petplace.com article “Cruciate Ligament Tear in Dogs” and read about the diagnosis and treatment of this condition.
I hope this article helps you understand more about cruciate injuries in dogs. Best of luck with your pup.


Dr. Debra