How does the automail work?


An automail must be a masterpiece, as the user seems to be able to use it as a
fully working arm/leg/... It seems however, that it's no regular artificial
limb.

What's so special about an automail? How does it work? Are there any
drawbacks?




[@kuwaly](https://anime.stackexchange.com/users/93/kuwaly)'s
[answer](https://anime.stackexchange.com/a/3840/274) covered most of it, but
here's a bit more information as well.

> What's so special about an automail?

It's basically a prosthetic limb which has been optimized for fighting. Its
name comes from [auto-](http://en.wiktionary.org/wiki/auto-) (as in
"automotive") and [-mail](http://en.wikipedia.org/wiki/Mail_\(armour\))
(related to armor). They were originally designed to give more freedom of
motion to uses of prosthetics, but were soon fitted to combatants who had lost
limbs.

There is nothing extraordinarily special about these limbs except their
versatility and wide variety of uses. Additionally, this type of technology
did not exist in the real world during the time _Fullmetal Alchemist_ is set
(early 1900s).

> How does it work?

There are dozens of little parts to it, but it is largely composed of motors,
tubing, and the external metal covering. Here's a couple images of its
components (click to enlarge):

[![Shattered automail \(2003
anime\)](https://i.stack.imgur.com/SsSygm.jpg)](https://i.stack.imgur.com/SsSyg.jpg)
[![Shell-less automail \(2009
anime\)](https://i.stack.imgur.com/zqiTym.png)](https://i.stack.imgur.com/zqiTy.png)

It has no internal power source; it draws its power directly from the impulses
of the nervous system to run the intricate motors and other mechanics inside
it (and of course, to control which ones activate when). So, when the synapses
are sent, each part contracts with its motors, giving free, versatile
movement.

> Are there any drawbacks?

Of course--otherwise, why wouldn't people just cut off their limbs? ;)

kuwaly mentioned three major drawbacks:

  1. [It is painful to have installed](https://anime.stackexchange.com/a/5407/274) (nerve connections are painful--in real life, too).
  2. It is prone to breaking (just like a bone or limb).
  3. It creates a reliance on an automail mechanic for tuneups and fixes, and mechanics can make mistakes!

There are two drawbacks that weren't mentioned, though. One is that it is
quite painful during pressure changes; recall that when Ed went to the field
with Pinako to dig in the rain (2009 anime), he was actually forced into
vomiting due to the aching pain of the pressure system. The second is that the
material can work against you; iron and steel can cause issues like frostbite
when in cold areas, and are also quite heavy. (Some alloys alleviate this
issue, though.)




[@kuwaly](https://anime.stackexchange.com/users/93/kuwaly)'s
[answer](https://anime.stackexchange.com/a/3840/274) covered most of it, but
here's a bit more information as well.

> What's so special about an automail?

It's basically a prosthetic limb which has been optimized for fighting. Its
name comes from [auto-](http://en.wiktionary.org/wiki/auto-) (as in
"automotive") and [-mail](http://en.wikipedia.org/wiki/Mail_\(armour\))
(related to armor). They were originally designed to give more freedom of
motion to uses of prosthetics, but were soon fitted to combatants who had lost
limbs.

There is nothing extraordinarily special about these limbs except their
versatility and wide variety of uses. Additionally, this type of technology
did not exist in the real world during the time _Fullmetal Alchemist_ is set
(early 1900s).

> How does it work?

There are dozens of little parts to it, but it is largely composed of motors,
tubing, and the external metal covering. Here's a couple images of its
components (click to enlarge):

[![Shattered automail \(2003
anime\)](https://i.stack.imgur.com/SsSygm.jpg)](https://i.stack.imgur.com/SsSyg.jpg)
[![Shell-less automail \(2009
anime\)](https://i.stack.imgur.com/zqiTym.png)](https://i.stack.imgur.com/zqiTy.png)

It has no internal power source; it draws its power directly from the impulses
of the nervous system to run the intricate motors and other mechanics inside
it (and of course, to control which ones activate when). So, when the synapses
are sent, each part contracts with its motors, giving free, versatile
movement.

> Are there any drawbacks?

Of course--otherwise, why wouldn't people just cut off their limbs? ;)

kuwaly mentioned three major drawbacks:

  1. [It is painful to have installed](https://anime.stackexchange.com/a/5407/274) (nerve connections are painful--in real life, too).
  2. It is prone to breaking (just like a bone or limb).
  3. It creates a reliance on an automail mechanic for tuneups and fixes, and mechanics can make mistakes!

There are two drawbacks that weren't mentioned, though. One is that it is
quite painful during pressure changes; recall that when Ed went to the field
with Pinako to dig in the rain (2009 anime), he was actually forced into
vomiting due to the aching pain of the pressure system. The second is that the
material can work against you; iron and steel can cause issues like frostbite
when in cold areas, and are also quite heavy. (Some alloys alleviate this
issue, though.)

