Locating the canine clavicle
The dog clavicle is hidden in the brachio-cephalicus muscle and can neither be palpated nor be detected if evidence of it was awaited. This positioning follows from the leading of Do Dogs Have Collar Bones?, which explains why it is so hard to find. It also makes sense to express location in relation to history. Why Don’t Dogs Have A Common Collar Bone? describes how evolution shrank the bone to almost nothing, and today it hangs as a small relic in muscle. A clear difference to the human can be read at Dog vs Human Collar Bones: Key Anatomical Differences, in terms of touching and viewing this that is, further emphasizing why the clavicle of the dog does not show up.
The brachiocephalicus is a massive, strap-like muscle that extends from the back of the skull to the humerus. In it near the top shoulder there is a little rod of cartilage or bone two inches long. It doesn’t have articular surfaces, it is not attached to the sternum, and there is nothing to project out of. Consequently:
- You can’t feel it: No matter how gently you palpate the shoulder, there’s nothing bony that you can place. The clavicle is entirely covered by muscle and connective tissue.
- You can’t see it externally: There isn’t a bump or ridge; the region is smooth
- Imaging is necessary: On X‑rays the clavicle is seen as a slender, fine line in the muscle, if it does ossify at all. An echogenic cartilaginous form can be identified by ultrasound in some cases.
As I stand by veterinarians during x-rays, we sometimes see the tiny clavicle. Its exact location may vary between dogs and breeds, but it is consistently lying within the brachiocephalicus. Smaller dogs have little to no bone while larger dogs may demonstrate a more mineralized fragment,.
How to think about the dog collar
This whole bone is the collar of dog collars but keep in mind it’s a term for a band around the neck, not a skeletal feature. Because dogs do not possess a bony connection from shoulder to sternum, the collar and/or harness lays across muscle and ligament. As a dog trainer, I like harnesses that don’t put pressure on the fragile neck area. Without a focus bone, high-quality equipment becomes even more important.
Conclusion
Palpitating for a dog’s collar bone is as much about understanding anatomy as feeling a bone. The dog possesses a clavicle, but it is small and located within the brachiocephalicus muscle. And though you will never feel the dog’s supraspinatus, that knowledge can help show you where it is and let you visualize what your dog’s shoulder mechanics are doing to make more informed decisions about exercise or harness design.
