Cranial cruciate ligament injuries are quite common in domestic dogs. Fortunately, they are not particularly difficult for skilled veterinarians to diagnose. When presented with a patient limping on one or both of its hind legs, the veterinarian with initially do several things. First, she will take a thorough history from the dog’s owner, paying particular attention to whether the dog had any recent trauma that may have caused an injury to the affected leg (such as jumping off the couch, running too quickly down the stairs, jumping out of the back of the truck, zooming around the yard and skidding in the mud, etc.). She will especially want to know whether the lameness came on slowly or suddenly. Next, the veterinarian will examine the dog physically, from nose to tail. She will observe the dog’s posture when sitting, standing up and walking. She will palpate (feel) the muscles and bones of the legs, usually starting at the feet and working upward. The veterinarian will be assessing the stability or instability of the stifle on the affected hind leg. There are special manipulations that she will do on the rear legs that will identify whether the cranial cruciate ligament has been ruptured, torn or stretched. Most dogs accept these gentle manipulations quite well, without the need for sedation. However, depending on the severity of the injury, sedation may be appropriate for the dog’s comfort.