For reference here in Australia my wife has been asking to get mammograms for years now (in her 30s) and she keeps getting told she’s too young because she doesn’t have a familial history. That issue is a bit pervasive in countries other than the US.
We were taught a similar trick in physics - point your right-hand thumb in the direction that current (or electrons, same same) is travelling and the curling of your fingers shows the direction of the resultant magnetic field that the current creates.