The responsibility for the failure falls squarely 'on her shoulders'. [=she is completely responsible for the failure]
You can never feel confident in this business. You always have to be 'looking over your shoulder'.
He 'has had a chip on his shoulder' ever since he didn't get the promotion he was expecting.
(..) Don't let nothing happen to Mr. Jingle, okay? Here. You take him. Del. I can't have a mouse on my shoulder while... ...you know. COFFEY: I'll take him, boss. Just for now, if Del don't mind. Yeah. (..)1999 The Green Mile