Brewer's: Atlantean Shoulders
Shoulders able to bear a great weight, like those of Atlas, which, according to heathen mythology, supported the whole world.
Sage he stood, With Atlantean shoulders fit to bear The weight of mightiest monarchies.
Milton: Paradise Lost, book ii. 305–7.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894