If our arm or leg gets sliced off, why can’t our body recognize and repair the severed limb if it’s sewn back together?
In: Biology
When a limb is severed, our bodies struggle to reconnect the intricate network of blood vessels, nerves, muscles, and bones required for it to function properly, making it impossible to sew it back together effectively.
We can and do. The tricky part is connecting ALL the blood vessels and ALL the nerves, joints, tendons etc. Replantation surgeries are practiced, but they only happen within a certain time window (like hours) and usually only on some limbs where there’s a chance of it actually working like hands/fingers). It is also only used for some types of injuries (where there’s a clean sharp cut) because if the tissues have been severely damaged there’s less chance of reattachment. Few injuries are however nice and clean…
You totally can. The hard part is that if you want it fully functional you also have to reattach all the blood vessels and nerve endings together, they can’t find each other if they’re just ‘loose’ in the wounded area and you just sewed the skin back together. But people can and do get appendages reattached.
Here is an old news story about a guy who had both arms ripped off in a farming accident in 1992, was able to call 911 with a pencil in his mouth and get them reattached. But he had to undergo many surgeries, still has aches and pains, can’t fully bend them properly or use all his fingers perfectly, stuff like that. Still way better than having no arms though!
https://www.sj-r.com/story/news/2012/02/20/farm-accident-victim-john-thompson/63280142007/
You can. It is “just” pretty difficult, since you have to connect up all the blood vessels, lymphatic vessels, nerves, tendons, muscle fibers, etc. Its complicated procedure, and usually you end up with reduced limb function.
But “reduced limb function” is usually preferable to “no limb at all”
When surgeons re-attach severed limbs, they need to make sure the vascular system is re-attached and functional. The severed limb will quickly die before it could heal on its own without a sufficient blood supply
Back in 1983-84 a guy in my high school got his thumb cut off… his buddy, with him at the time, did some quick thinking and wrapped the severed thumb in ice and got him quickly to a hospital…. Surgeons were able to reattach the thumb and it was like 75-80% functional. The guy liked to show it off at parties and stuff
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