Which one? Her left elbow is partly hidden my Myternaster's hilt guard. Besides, Monty's art style is generally to make the girls' limbs quite skinny and 'stick figure'-like.
At least she's trying. Bless! ;-)
If Yang doesn't say that some time in the future, I'll be deeply surprised. I'm also expecting Ruby to kick ass at some point and Yang to remark: "Well, looks like Sis Rose to the occasion!" There will be a dead pause before Weiss, with a weird look on her face, replies: "Yes, she did. Why are you acting as if you expect us to do or say something?"