Too often I see commentators talk head and shoulder (or reverse head and shoulder) while in my view the chart does not reflect that pattern. Now, I may just be too much of a stickler for patterns but ...

The deltoid is a round muscle that goes around the top of your upper arm and shoulder. The main function of the deltoid is to help you lift and rotate your arm. There are three parts of the deltoid ...

The deltoids are the muscles that cover the front, back and side of the shoulder joint — and they are essential for everyday movements like raising your arms, lifting a child or carrying groceries.