In addition to his day job as Woot's full-time "Debunker," Jeopardy! wunderkind Ken Jennings moonlights as an author of books, and this month he has a new one in stores. It's the fifth in his Junior Genius series, this time chock-full of amazing facts about The Human Body. To mark the occasion, he'll spend all of February debunking anatomical anachronisms and medical misinformation for us. Finally: the inside scoop about our own insides.
The Debunker: Is the Heart on the Left Side of Your Body?
With Valentine's Day coming up, we're all more aware than usual that there's no greater mystery than the human heart. But it would probably surprise you how little most people know about their own heart. Including where it even is.
During the Pledge of Allegiance or national anthem, Americans put their hands "over their hearts," unless they are a zoned-out politician about to appear in a chain e-mail from your grandma. Everyone else automatically puts their right hand over the left side of their chest—because that's where the heart is, right? Nope.
Your heart is actually centered right in the middle of your chest, on your body's axis of symmetry. In a chest x-ray or MRI, you might see that the heart bulges or tilts slightly to the left, because those are the heart's strongest chambers. (The right ventricle only has to get blood into the lungs, which are just next door. The left ventricle is what pumps oxygenated blood into every other part of the body.) That's why you may feel your heartbeat more strongly on the left side than the right. But that doesn't mean your heart is on the left. That's where your left lung goes.
A small number of people have a condition called dextrocardia, in which the heart is flipped and actually tilts to the right. Sometimes this mirror-image anatomy extends to all their organs, an even rarer condition called situs inversus. Donny Osmond is a famous situs inversus sufferer, and his weird alien physiology almost got him killed one time as a kid when he had serious appendicitis and doctors kept misdiagnosing it. Does this mean Donny should say the Pledge of Allegiance with his left hand over the right side of his chest? I don’t know. I just don't know.
Quick Quiz: In the bestselling book Where the Heart Is, what unusual place does teen mom Novalee Nation give birth to her baby?
Ken Jennings is the author of six books, most recently his Junior Genius Guides, Because I Said So!, and Maphead. He's also the proud owner of an underwhelming Bag o' Crap. Follow him at ken-jennings.com or on Twitter as @KenJennings.