Soft Tissue Injury
This is the most common cause of limping for dogs. They include sprains, muscle pulls, and similar minor traumas. They are not serious, and can be successfully treated with a few days rest, and a mild analgesic.
If your dog has increasing difficulty with getting up after lying or sitting for some time, or trouble with climbing stairs or getting into and out of its bed, check with your vet about canine arthritis. If you have a large dog, hip dysplasia might be present.
Footpad or Paw Injuries
Look for cuts on the footpad. Also look for splinters or other foreign objects (thorns, sharp stones) imbedded in the footpad, or between the toes. Check for broken claws. Be alert for swelling or other possible signs of infection in this entire area. Extreme weather conditions can also cause painful cracks in the tissue of the footpad.
These injuries are bone fractures where the skin is not broken. They may not be immediately evident because the leg may not look misshapen or twisted.
This is a very serious type of bone fracture where the broken bone punctures the skin. This exposure often causes dangerous infections of the bone.
Epiphyseal and Greenstick Fractures
Epiphyseal fractures usually occur at the end of the long bones (femur, humerus) in puppies and young dogs. These areas are called growth plates, and because they are not matured, the bone there will soften and fracture.
A greenstick fracture is a crack in the bone. The bone is otherwise intact.
A more scientific medical term for this complaint is Panosteitis. It is, of course, found in puppies and young dogs and usually does not need treatment.
Ligaments are the bands of muscle tissue that knit bones together at the joints. When they're injured, stability of the joint is compromised or destroyed, and your dog's limping will get progressively worse over time.
Limping is a symptom associated with tumors in or on the bones, or in the brain or central nervous system. If you see suspicious symptoms accompanying your dog's limping, such as dizziness or disorientation, or if you find any odd lumps or masses, get your dog to the vet as soon as possible. Tumors are often life threatening, and time is of the essence.
Your dog's knee can adopt a sudden and dangerous side-to-side motion for various reasons, (trauma, infection) and the knee will slip out of alignment. The knee can also pop back into alignment just as quickly. Be watchful for recurring problems with this if you have a small dog.