You're working with the Peace Corps in Peru. The owner of a small herd of free-foraging pigs comes to you and says he found one of his pigs dead in the front yard, a few days after it began to develop symptoms of ataxia and lameness; he's worried that there's a contagious disease that will infect the rest of the herd, and asks you to do a postmortem. When you do it, you find that this pig had a couple of major aneurysms and that one has burst.

Points to ponder:

1. What's an aneurysm? What has happened to the wall of this aorta, and why did it happen?

2. Why does this condition tend to occur in large arteries close to the heart most frequently?