All of us Anatomy TAs were freaking out yesterday, excited to see a situs inverus cadaver. (Situs inversus occurs when all your organs are flipped to the opposite side. So your heart’s on the right, your liver’s on the left, etc.) I was helping people dissect yesterday when I saw one of the team’s bodies where the apex of the heart was pointing toward the *right*. First I thought, “Did they detach the heart and flip it around? But it was firmly stuck in there. I started to get excited, thinking it had to be situs inversus, so I felt down toward the *left* side of the diaphragm, and felt the liver. There it was!
I called the professor over to confirm it, and he agreed–it was the first case he had ever seen. Very exciting. The whole lab swarmed to check it out, and I called the other TAs over to see it. Absolutely fascinating. I can’t wait to see the abdomen.
Situs inversus is a 1/10,000 occurrence, and some believe it occurs due to a mutant cilia protein that causes the cilia to beat in the opposite direction. This then pushes developmental proteins in the fetus to the opposite side, and voila, mirror image.
Unfortunately for the dissecting students, they’re going to be *totally* confused. I told them to make sure they primarily study different bodies… otherwise, they’ll be totally lost.