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.
(..) Well, I say I'm sorry, and... ...well, I am sorry. Come on, Sergeant. Lock that door. Pull down the shades. Ashley. It's all right. It's only in the shoulder. Get him on the bed where I can dress the wound. I think I can walk. It's not worth the effort. Which way? In here. (..)1939 Gone with the Wind