Reattaching a severed body part sounds pretty delicate but straightforward: Sew it back where it once was. Well, no, that is not always the case. It sounds like science-fiction, but sometimes the best way to reattach a severed limb is by first attaching it somewhere else on your body. Somewhere unnatural.

No matter where surgeons attach an errant limb, the process involves restoring blood flow in the appendage by reconnecting the arteries, through which blood enters the body part, and the veins, through which it leaves. Slate explains that the severed tissue must still be alive and the blood vessels have to be big enough “to manipulate using microsurgical techniques.” If veins cannot be sewn together right away, surgeons may use leeches to suck up blood flowing through the limb in order to prevent buildup and swelling: “A chemical in its saliva, hirudin, keeps blood from clotting and allows continued drainage.” When the limbs are in their final resting places, other pieces that must be reattached include tendons, bones and nerves.

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“In general, the cleaner the cut, the more simple the operation,” Slate says. “Ears, which have small arteries and which, when severed, are often ripped off or bitten off, tend to be tricky.”

But at times, it is not possible to reattach a body part where it belongs right away. In one case, a Chinese factory worker’s severed right hand was attached to his left ankle to keep it alive while the surgeons repaired the rest of his arm. The International Business Times reports that the arm had been “flattened” in the machine accident. Eventually the hand was reattached.

Commenting on that case across the world, Dr. Cairian Healy, of the Royal College of Surgeons in England, told the BBC, “The concept of saving a severed part of the body by attaching it to another part of the body to give it a blood supply is well recognized.” He added, “The ankle is a hard place to graft though. Usually surgeons would go for the armpit because the blood supply is better.”

In other situations, doctors may grow a new part somewhere on a person’s body and then cut it off and reattach it where it belongs. The International Business Times has also reported on a case, again in China, where doctors grew a nose on someone’s face after a car crash severely damaged his original schnoz. They used cartilage from his ribs and inserted it into his forehead, which then was manipulated to grow the tissue necessary for the new nose’s flesh. That is not an isolated incident; ears have been grown on arms, a skull on a stomach, and a finger on an abdomen.

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