>>7641572
You're a million times better than me so it's probably my eyes playing tricks on mme but the deltoid muscles are the upper muscles that connect to the shoulder. In your pic, the right arms feels like it bends to a width just slightly thinner than what I feel it should bend to, but that's probably my inexperience with the angle.

Picrel I suppose but I'm not entirely sure if that's correct, probably not.