Latissimus dorsi and Erector spinae

Latissimus dorsi is a superficial muscle that covers the largest part of the back. It’s form is diverse and influenced by many factors. The picture shows how the erector spinae deep muscles influence the form of Latissimus dorsi.

Erector spinae is a group of three muscles with a joint function – it can be thought of as the abs of the back. This muscle group allows to straighten the back and provides for side-to-side rotation. When it’s flexed, it influences the surface forms of Latissimus dorsi. Check it out yourself on the 3D model: ecorche.anatomy4sculptors.com