How are performers able to "swallow" swords without harming their body?

Question

While I recognize that most magicians and street performers that "swallow" swords are most likely doing an optical allusion, some people have actually done this correct? How is it possible for individuals to put a sword in their mouth and down their throat without perforating their internal organs and without choking themselves? I understand that there must be a lot of training involved, and even with training, it's always risky (I would never do this!! And neither should you!! haha), but how do they physically do it without harming themselves?

This is an image of what I'm referring to:

Answer 1

I had an uncle that could do this trick, and it always amazed me.

"Swallowing" the sword is really just letting it slide down your throat, but this is much harder than one might think. It requires the peformer to relax all the muscles in the throat (and resist the body's natural urge to gag or get the object out) - this requires a lot of practice.

Perhaps it's obvious, but I should mention that they always use a sword with a dull blade.

So it's not exactly "swallowing" a sword - instead, the performer relaxes his throat muscles, allowing the blade to enter the esophagus.