Multiple Sclerosis
When the inner parts of the body are forming, roadways are laid down.  Similar to how when building a big city, roadways are needed for people to travel in and out, back and forth to and from the city, the body's roadways are designed for the travel (or flow) of three things: nerve energy, blood, and cerebrospinal fluid.  Nerve energy flows back and forth between the brain and the body, giving life to all the vital organs such as the lungs, immune system, and heart.  Blood flows to and from the heart, bringing nutrients and oxygen to the rest of the body.  Cerebrospinal fluid flows all around the brain and spinal cord, giving nutrients to the discs in between each vertebra, cushioning the aforementioned areas, and in general keeping us moving fluidly.
Boom!  There's an accident on the roadway leading into the big city.  What do we get?  A traffic jam.  Some people decide that sitting in traffic is not their bag, so they exit off and try to find an alternate route. 
Boom!  There's an accident called a subluxation that creates a similar traffic jam in the body.  Nerve energy flow is disrupted, decreasing the normal function of the heart, lungs, and immune system (to name a few).  Blood flow is disrupted, causing the heart to work harder to pump blood throughout the body.  And cerebrospinal fluid flow is also disrupted.  Let's focus on the cerebrospinal fluid.  Some of it decides that it'd be smart to exit off the normal route and find a new way to flow.  Unfortunately, there's really nowhere for it to go.  It's reached a dead end.  So, it pools up in a tiny spot.  In the meantime, some more of the cerebrospinal fluid saw what its brother was doing and decided to exit off in search of an alternative route, too.  It didn't fare any better.  So, now we've got these little pockets of fluid pooled up around the spinal cord and brain with nowhere to go.
Honestly, it's really not that big of a deal...that is until the compromised immune system, designed to protect us from foreign invaders, recognizes that there are pockets of fluid around the spinal cord and brain that shouldn't be there.  It incorrectly assumes it should attack.  So, it attacks...and attacks...and attacks.  It destroys...and it destroys...and it destroys.  What's left is tiny areas of scarring, called sclerosis.  Multiple areas of scarring is called multiple sclerosis. 
The lesson to be learned is that when the top bone in the spine misaligns, it chokes the brainstem and all it's surrounding roadways, including the nerves, arteries, and cerebrospinal fluid pathways.  By removing the pressure on the brainstem, the traffic jam is cleared and the immune system returns to its normal function.  The immune system recognizes the areas of sclerosis (scarring) and sends help to repair them.  Some people are fortunate enough to develop out of the condition from that point forward.  Others may still be symptomatic, but the severity of their symptoms may decrease tremendously. 
There's literally nothing that the body is incapable of when it doesn't have to deal with the subluxation choking the life out of it...