Carrying a heavy burden...

Derail I know, but "standing on the shoulder of giants"... Surely it should be "shoulders of giants", or "shoulder of a giant"? Am I missing something?

I posted that to illustrate a previous wrong usage of 'shoulder'. It became famous mainly through Oasis obstinately insisting that the singular had been deliberate when there was a very strong whiff of suspicion that it hadn't been. (You must know that the originator of the phrase was Isaac Newton.)