The joints, in collaboration with the rest of the bones and muscles, let the body move. There are three types of joints: mobile (diarthrosis), semi-mobile (amphiarthrosis) and fixed (synarthrosis). Most of the joints are mobile and link with the bony ends to facilitate their movement, such as the knee. The semi-mobile joints individually have little movement, but together they can produce flexion, extension and rotation, as in the case of the vertebral joints. The fixed joints are rigid joints that do not require mobility, like those of the skull. Most of the joints are called synovial; its characteristics are mobility, versatility and lubrication. This infographic from the Ábaco collection is integrated into the Human Body series, which includes also the original titles: Skeleton, Woven Bone, Skull and Face and Body Axis.