In a nutshell, chiropractors adjust your spine to remove pressure or interferences to the nerves that connect your brain to your body. Chiropractors call these interferences subluxations. Left there long enough these subluxations will result in your body developing symptoms. Depending on which part of your nervous system is being interfered with determines the type of symptoms you may develop.
For example, some people with pressure in the upper neck develop interference to the nerves for the scalp, face, eyes, and so headaches or migraines may result. Others with interferences to the lower back can display leg pain (sciatica) or irritated bowels (diarrhoea/constipation). Detection and removal of interferences to the nervous system is a Chiropractors specialty and is why we are able to achieve wonderful results with a large range of presenting complaints.
In many cases delivering the adjustment to your spine to help remove subluxations and allow your body to heal is the easy part. Knowing specifically which level to adjust, in what direction with how much speed and amplitude is the hard part. This is why it takes Australian trained chiropractors five years of university study in order to be registered to do what we do.
For an overview of what we do, take a audio guided tour via the following YouTube link.