http://www.ardecol.ac-grenoble.fr/english/ellisislandwebquest.htm

Describing actions is a key element of narrative. Hammett's terse, hard-boiled style is very visual, very concrete. He rarely bothers with what characters are thinking. Instead, he shows us through body language. Under Hammett's pen, we see the characters' eyes, faces, gestures and the way they hold themselves. That's why knowing the vocabulary for parts of the body and for specific ways of looking, speaking, standing, walking and gesturing are so important. You find the same sort of approach to descriptions with many writers, to a greater or lesser degree; don't forget that nearly all the Bac exams are build around novel extracts that often contain quite specific descriptive language that you need to know to understand the subtleties of the characters and situations.