Dogs and Shoulders
Sylvia 
Understanding your dog's shoulder structure is an important aspect of their overall health and well-being. Knowing the intricacies of how your dog's bones and muscles work together can help you better care for their needs. With proper attention, you can help ensure your furry friend stays happy and healthy for years to come.
Did you know:
The dog’s shoulder blades (scapula) sit unattached from the rest of the dog's skeleton. This allows for greater flexibility and stride length. Unlike humans, the dog's shoulder are partially disconnected from the skeleton. They are completely unattached at the top but there are several muscle and ligament attachments at the bottom. This is why they are such great runners!
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Dogs don't have a clavicle. The simple nature of the bony anatomy means that the stability and function of the shoulder are closely controlled by ligaments, tendons, muscles, and the joint capsule and it is injury to one of these structures that is the cause of the lameness.
Dogs also weight bear on their shoulders, unlike humans. Dogs carry 60% of their weight on their front limbs.
According to Ridge Referrals, the cause of the injury can be very diverse with some cases presenting after a sudden lameness associated with a single episode such as a fall or colliding with another dog at speed. Most however are either chronic (long-standing) weaknesses or repetitive strain injuries where a single action is repeated many thousands of times creating micro trauma to a structure or structures that build up over time.
A shoulder injury in dogs can be a troublesome thing to diagnose and treat, often because the signs come and go. It cannot be found on an X-ray unless it is resulting from the elbow joint. Then a CT is recommended.
All dog breeds and ages can be affected, but it is seen more often in larger breed dogs.
So spare your dog's shoulders, and assist with jumping off of heights, do not let them jump onto slippery floor which can cause injury, or partaking in sports that could stress this area of their body.