No, I Will Not Be Your Girlfriend

The human heart is on the left side of the chest, not in the middle of the ribcage where it seems it should be. There is a balance to the body, after all. If you have two of something, they’ll be evenly spaced on each side of a line drawn down your middle, for example your arms, feet and nipples. If there’s only one of something, it’ll be right smack in the middle on that line, like the nose, the mouth, the belly button. So the heart, since we each have only one, should be in the middle of the chest, behind the sternum. This, however, is not the case. Evolutionary biologists figure that the sternum is a structural weak point, the joining of the bones of the rib cage. Things are most likely to break at a joint—imagine a falling boulder, a kick from a mastodon, a spear tip. So, evolution must have selected for people whose hearts were a little to one side of this vulnerable area. Time goes on, this effect becomes greater, and today our heart is to be found securely on the left side of our chest, behind a safe, unbroken wall of ribs. This is a good idea from the standpoint of the preservation of life. As well, it illustrates the innate ability of the human heart to get out of the way of danger.