hogarth anatomy studies

Been getting in to Burne Hogarth's book of late, trying to gain a greater understanding of anatomy. Yesterday I started at the head and am working my way down the body. i am currently on the arm and how it connects to the torso

Picked up an interesting bit of info about the muscles of the torso. The torso divides into three parts: top, middle and bottom. The muscles of the top are purely designed to move the arms, the same goes with the bottom section for the legs. and the muscles in the middle section are there to move and support the top and bottom.