Board Thread:Boruto Discussions/@comment-33255203-20171004210031/@comment-30323490-20171022174216

More times than none the Susanoo had to be empowered step by step, so of course Madara would start with the rib cage...but i'm pretty confident that if he would've only kept the rib cage on, it would've been torn apart by the UBBR...hence why he didn't and why he evolved it immediately to the humanoid version...