CT scans 3D reconstruction and visualization gets more and more involved in medical practice. To get knee realistic anatomical parts 3D views, we developed image segmentation and fast voxel based visualization tools. Knee serial transverse CT scans were taken with SOMATON DR3 (50 contiguous scans, 4 mm collimation, 256 by 256 resolution), then sent to a graphic workstation. Images were segmented using either single density criteria for bones either texture criteria in order to distinguish the different muscles and tendons. 3D reconstruction and visualization was completed with a voxel raytracer software using both original CT scans and segmented images. We developed all software works on Silicon Graphics workstations. Segmentation clearly shows compact and spongy parts on each bone. The knee joint muscles and tendons have been also identified. Realistic 3D visualization of the whole knee or single muscle, or group of muscles are achieved in a short time. Interactive cut-planes, color-table, opacity factors, segmentation choices and observer position make it easy to build animations. Knee joint fast realistic 3D visualization allows powerful tools for anatomy teaching. Moreover, included segmentation process helps anatomy understanding and can be used for orthopedic aims, giving shapes and volumes of each anatomical part in the joint.