Are you an avid crossword solver but get a little stumped every now and then? Well you've reached the right place! Here we will help you find the answer to the clue Flat back muscle, briefly from Universal crossword. Once we've looked for any additional hints from inside the Universal crossword puzzle and gathered any other information that can help us find the answer to the clue Flat back muscle, briefly, we can finally conclude that the possible answers for the clue Flat back muscle, briefly are: