We're going to stick around in the back and look at a duo of muscles that really contribute to the shape of the human body.

Latissimus Dorsi - A large, flat muscle on the back, also known as the "lats," that extends from the lower back to the upper arm. It is responsible for movements such as pulling the arms down and back, as well as internal rotation of the shoulder.

Teres Major - A muscle in the shoulder that helps with arm movement. It originates from the bottom angle of the scapula and inserts onto the humerus.