In the Dark Knight Rises, we are introduced to the character Miranda Tate, who becomes physically involved with Bruce Wayne.
During their tryst, we see a peculiar scar shaped like an upside down 'U' on her back. Bruce traces it with his finger, but he doesn't comment on it or otherwise realize what it is.
Later we discover that
Miranda Tate is Talia Al'Ghul, daughter of Ras Al'Ghul and member of the League of Shadows. I initially thought the scar was a League of Shadows mark, but if so, why wouldn't Bruce have noticed that earlier?
What did that scar really signify?