The upper arm is closely related to the shoulder girdle and they support each other in the human anatomy, not only in terms of construction and mechanics, but also in terms of expression, and should be shown as connected in any human figure drawing. The flow of shapes and overlapping forms continues from one to the other, and in figure sketching specific attention should be paid to how these two areas inform each other visually speaking.
This video is from figure drawing instructor Robert Stollar, a self-taught sculptor with a passion for figure drawing. A passion and, of course, a necessity. He lives in Sydney, Australia with his beautiful wife and three dogs, working as a sculptor and teaching figure drawing.
For those who cannot attend his classes in person Robert has an online version of the lectures at Figure Drawing Online.