I know that both words mean "arm", but is there any real difference between 手臂 and 胳膊? When I started to learn Mandarin at university, they taught me to use 手臂, but now I see that 胳膊 is the one included on the HSK4 vocabulary list.
Is there any difference regarding the "part" of the arm that they represent? Is it a matter of one being more formal than the other?
Best regards