Air carrier Flight Attendant reports wake turbulence encounter during final preparation for landing resulting in injury to the reporter. The wake was reportedly from a B747.

Narrative

Our aircraft was on the decent. Myself and the Lead Flight Attendant were in the aft galley. The compliance check had been completed and all the passengers were secured in their seats at this time. The Lead and I had finished our garbage collection and cleaned up our galleys and he had brought back trash to be in the aft bin. He was sitting on the jumpseat (not strapped in) and I was standing in the aft galley. He was going to go back to the front when there was violent noise (BANG!) and without warning I was thrown to the floor and when I fell I hit my head on the R2 door. I was dazed for a few seconds and the Lead was asking if I was ok. When I thought I could get up he helped me get up and get to my jumpseat; as at this point we were close to landing. The Captain had told us when the plane landed that it was wake turbulence. He said that by the time they noticed there was a 747 nearby they were in the way of its wake and could not make any corrections. For a few days afterward I had a bump on my head and it was sore and my arm that I landed on swelled a little and also was tender to the touch but I did not feel at that time that I needed to see a physician. The only thing I can think that may have avoided the situation would be if the pilots would have noticed the 747 sooner and been able to somehow get out of the way of its wake but I understand that that may not always be possible.