technically the legs have 3 joints… the shoulder joint is usually pretty immobile, more like a shock absorber than a joint.
 
except mlp ponies break that rule when they’re doing into “hug” mode.
 
but for ponies standing like ponies, the “upper arm” points toward their front, like a “<” formed from their scapula and humerus. if you really wanna be horse-accurate, draw the back edge of their upper arm, but have the front edge just merged with their torso. the “back edge” is actually connective tissue between their elbow and their side. their “armpit” is actually a good deal away from where their actual shoulder is.
 
regardless the elbow should be alongside the barrel, not just below it.
 
yeah I obsess over this stuff too much. even the show animators get it wrong, and it looks fine.

@ABronyAccount  
You got it, next time: Beaks!

Also, don’t draw ponies with dog lips.

@Amateur-draw  
Heheh yeah, I’ve never really made a guide for it so I tried to only keep some important details in it. Maybe next time I oughta redo it from the ground up.

Looks helpfull and hard at the same time.