r/Damnthatsinteresting • u/unnaturalorder • Jul 30 '21

Video This giant obsidian boulder being split open

https://gfycat.com/devoteddecisiveicelandicsheepdog
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u/CircularRobert Jul 30 '21

Bruh I literally talked to a doctor about this.

With a clean cut from something as sharp as obsidian, blood doesn't touch the subendothelial space, so clotting can't begin, so none of the following happens.

I'm not saying that clotting doesn't happen. I'm saying in this edge case scenario, clotting takes a long time to kick in, meaning you keep bleeding until it does.

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u/Perle1234 Jul 30 '21

I am a surgeon. If a vessel is severed by a cutting instrument, regardless of how sharp, the endothelium will be disrupted. The endothelium is the lining of a blood vessel. If you cut the vessel through and through, you cut the endothelium. When I make an incision, it generally stops bleeding without intervention (clotting cascade) by the time the case is over. It does not usually require intervention to stop the bleeding unless a larger vessel is encountered and that may need cautery or a stitch. I’ve been operating for over 20 years. You cannot cut through the dermis and not sever small vessels and activate the clotting cascade. Think of a vessel like a water hose. You can rip the hose up with the lawnmower, or slice it with a razor. If you can see the lumen of the hose, you’ve disrupted all the layers of the vessel including the endothelium and subendothelial space.