I Have A Right Side Lower Back Problem Which Gives

I have a right side lower back problem which gives me grief down the front of my right leg. I been informed by my osteopath that this is the Femoral nerve giving the trouble and not the Sciatica nerve, at present I need an injection to ease the pain, so what area should be injected ?, L4-5 OR L2-3. I await your reply. Regards Stan