>>42314481
they are called human shoulders because of the exaggerated clavicles, making it kind of look like a pony head on a human upper torso. in most cases it's slight enough that it doesn't deviate from pony perfection much (a few times in the show they extend the clavicles a little bit too), but in that image it goes too far imo
pony shoulders kind of jut out of the barrel directly kind of like an actual horse, so if you take away the legs from a pony they would look like a slug thing with a barrel continuous to their neck, whereas if you take the arms away from a human you would get little wings on the side from the clavicles
in the right image you can see how the limb anatomy is only is visible beginning at the point where the humerus pokes out, unlike human shoulders