Why Does the Vet Check My Dog’s Armpits?

Q: When I take my dog in for his annual exam, I’ve noticed the vet checks certain places for swelling, like in his armpits. There hasn’t been a problem, but I’m wondering what this is about and whether it would help if I checked them at home?

A: Your veterinarian is checking for swelling in the lymph nodes, and yes, it would be a wonderful idea for you to know what they normally feel like so you can notice any changes.

So what are these things? Just as your mom used to feel beneath your chin and along your throat when you were sick, the veterinarian routinely checks a dog’s lymph nodes for signs of illness. 

When all is well in the body, the lymph nodes are usually so small that it's hard to find them unless you have a medical degree. They're about the size of a bean and located under the dog's jaw, at his collarbone, in his armpits and groin, and at about the midpoint of his rear legs. When something is wrong in the body, the lymph nodes swell as they help fight infection or injury. Swollen nodes can indicate a wound, virus, infection or some other illness.

For example, I once treated a dog who had picked up a weed's seed spike (also known as a foxtail or cheatgrass) that burrowed deep inside and caused an infection that couldn't be seen. But the swelling in a single nearby lymph node told me that something was going on and helped me to find the problem.

At your dog’s next exam, have your veterinarian locate these spots for you. Once you can find them and recognize what they normally feel like, you may be able to tell when there’s swelling. And that means it's time to call the veterinarian.