Q: Principles of biosignals (partic. EMG)

[Stefan Kolodzie]

Hello, 

while I'm working with EMG, I wondered if someone can tell me, what 
processes make the EMG, measurable with _surface_ electrodes. Do I measure 
electric fields originating at the synapse or do I measure ion currents 
(besides the ion currents from the skin to the electrode material)? Of 
course, both processes are mutually dependent, but which of these processes 
are - say - stronger at the electrode?

TIA, Stefan