Upper Back Muscles Diagram / Upper Back Muscles Diagram Quizlet . The superficial back muscles are the muscles found just under the skin. These are situated at the back of your upper arms. Luckily you've found this page to help you. The muscles of the back that work together to support the spine, help keep the body upright and allow twist and bend in many directions. Dummies has always stood for taking on complex concepts and making them easy to understand. Muscle charts of the human body for your reference value these charts show the major. Muscles of the back can be divided into superficial, intermediate, and deep group. Intermediate back muscles and c. Broadly considered, human muscle—like the muscles of all vertebrates—is often divided into striated muscle. The deltoid, teres major, teres minor, infraspinatus, supraspinatus (not shown) and subscapularis muscles (not shown) all extend from the scapula to the humerus and act on the trapezius and latissimus dors