Hi again Ellie,
I have used google to try get you some information but there are so many links coming up and not sure which ones of any use.
It may take you a while but maybe best if you go through them yourself rather than me keep posting loads of links here.
In google I just typed in what you said.. 'brachial plexus'
There are descriptions there,treatments,therapy etc.Hope its what you're looking for.
Rosemary