Dog with a swollen left elbow

History of Present Illness

An 8-year-old neutered male Giant Schnauzer dog is brought to the clinic by his owner because the dog's left elbow is swollen. The owner first noticed the swelling about a month ago while the dog was playing with toys. At that time the dog yelped and was noted to be lame. Since then, he has been intermittently lame and sometimes appears stiff.