How can I check to see if the jets are blocked to my rear wash wipe?

I have a Nissan Micra Urbis 2005 1.2 It seems that the pipe/jets must be blocked as no water comes out when pushing the stalk back. Don't think its the motor as I can hear it working The rear wiper blades work on all the functions - just no water comes out. I have also checked the screen wash bottle and that is more than half full. I can't see any jets on the rear window or the blade to try and unblock them.