In representational figures it's highly important to know as much as possible about the surface anatomy (skeletal and musculature system that affects the surfaces of the skin. For instance in my Sustained Figure Concepts class, Week 3's lecture talks about the flexors and extensors of the forearm that are generally grouped together for all intents and purposes of drawing. With that said knowing each individual muscle of each group is not necessary.

I believe the creative expression of the artist in drawing representational figures is contingent on the gesture of the pose....since it is the embraced as the story or the essence of the pose and movement of the pose. Without solid knowledge of the anatomy (proportions and muscular/skeletal structure, male and female differences) I would find it difficult to exaggerate the pose or create something more dynamic than what is presented by the model.

In each drawing we had to do the past 2 weeks everyone in my class drew specific areas of tendons whether they knew it or not. In some models and poses tendons are even more pronounce and if the artist has limited knowledge of the anatomy this can give their drawing a funny appearance (I know this from experience):

Surface Anatomy: Tendons The entire top of the hands and feet are a system of tendons from the extensors and the knee joint itself is a system of tendons all the way around.

I've spent many years learning about the anatomy of the figure and will most likely spend the rest of my life doing just that.