In this paper we propose a method for the automatic extraction and annotation of the animation control skeleton of virtual humans, which relies on an a-priori knowledge of the human anatomy. The method is based on a segmentation of the virtual human shape into semantically meaningful features, like arms or legs, and on an automatic location and labeling of joints of the control skeleton. The method is particularly relevant for computer animation where the process still largely relies on manual tasks, and especially for virtual characters built on real scanned data. Several examples will show the results obtained with our approach.