By Dr. Elizabeth Knabe, DVM
Wildwood Animal Hospital and Clinic LLC
A while ago I wrote about elbows and how they were often overlooked as a source of problems for dogs and cats. Now I want to touch on the canine shoulder, since it is a complex and very important joint as well.
As in humans, the dog shoulder is a ball and socket joint surrounded by a capsule of tissues and supported by multiple ligaments and tendons. Unlike in humans, the dog has no bony collarbone and instead has a small segment of tough tissue embedded in one of its muscles in front of the shoulder.
The dog has a very narrow chest compared to humans, and it doesn’t need a collarbone to keep its front limbs apart from each other.
When a joint is put under unusual stresses over time, things can happen that we call “wear and tear” injuries, where some of the shoulder support structures undergo degeneration; this leads to rotator cuff issues and arthritis in some dogs.
Think of English bulldogs and other breeds that stand and walk with their elbows flared outward and realize the stresses they are placing on their shoulders over time.
Obesity is a prime factor in putting too much stress on the shoulder joint, especially since dogs carry about 60 percent of their weight in the front limbs already. Even young dogs can have shoulder problems.
Osteochondritis dissecans (OCD) is a condition seen in young, large-breed dogs. The growing bone of the upper limb fails to fully become bone and instead retains bits of cartilage. The cartilage is weaker and breaks off in flaps or becomes free pieces within the joint. This is painful and will need surgery to correct it.
Less common, bone cancer can occur at the upper limb bone right near the joint. This is usually very painful, and the dog will often have a significant limp, versus a milder one for some of the other conditions.
Some other less common shoulder problems involve infection within the joint and dislocations, due to trauma.
Anytime your veterinarian is examining your dog for front limb lameness and suspects a shoulder issue, they will often want to take x-rays. Realize that if the limb is painful already, they will want to provide for your dog’s comfort by doing the x-rays under sedation; this also allows for correct positioning which reduces retaking films and decreases exposure to radiation.