Which muscle is this and how to build it?
In a lot of. Arnold Schwarzenegger bodybuilding pics, especially the side chest ones, there is a muscle jutting out of back.
I have posted a pic here. https://www.tumblr.com/aks2161989/774077064229912576/which-muscle-is-the-circled-part
Check out the circled part
What muscle is this? Which exercises should you do to build this muscle?