What are the muscles in a dog’s rear right leg that could be torn and which way does the tail wag if they are happy. I am just curious and a little worried about my dog? Please respond as soon as possible and thank you so much for your time and effort. PG, Connecticut

Dear PG,
Maybe you’re talking about a torn knee ligament or ruptured anterior crucial ligament (ACL), a very common cause of rear limb lameness in dogs? If so, this is a serious condition that should be seen right away by a veterinarian for diagnosis and treatment, which may involve surgery.

Now as far as tail wagging, there are some folks who say that a wag is a wag is a wag. “I can tell you a dog wagging its tail in a full circle is a very happy dog” says Penny Lane, a professional dog trainer and educator from Pennsylvania.

However, a team of Italian researchers found that dogs wag to their right side when feeling positive emotions and to their left side when feeling negatively. They claim this bias has to do with which side of the brain processes the information, with positive emotions handled by the brain’s left side and therefore expressed on the dog’s right side while negative emotions are handled by the brain’s right side and expressed on the dog’s left side.

Apparently other dogs can tell which way a tail is being wagged and adjust their approach accordingly to the wagger. Now it’s just up to humans to become better at reading dogs and interpreting their emotions!

About Dr. Lydia Gray

Lydia F. Gray, DVM, MA SmartPak Staff Veterinarian and Medical Director Dr. Lydia Gray has earned a Bachelor of Science in agriculture, a Doctor of Veterinary Medicine (DVM), and a Master of Arts focusing on interpersonal and organizational communication. After “retiring” from private practice, she put her experience and education to work as the American Association of Equine Practitioner’s first-ever Director of Owner Education. Dr. Gray continues to provide health and nutrition information to horse owners through her position at SmartPak, through publication in more than a dozen general and trade publications, and through presentations around the country. She is the very proud owner of a Trakehner named Newman that she actively competes with in dressage and combined driving. In addition to memberships in the USDF and USEF, Dr. Gray is also a member of the Illinois Dressage and Combined Training Association (IDCTA). She is a USDF “L” Program Graduate and is currently working on her Bronze Medal. Find Dr. Gray on Google+