A skeleton was the bony structure that supported the body of many organisms in most species. People with skeletons had weak points in their limb joints and skull, making these points more susceptible to injuries. Some people suffered from degenerative bone disorders, and could have their skeleton augmented with high-impact polymers. Because the skeletal reinforcements had to be integrated with the subject's tendons and ligaments, an oversight could result in chronic muscle fatigue as muscles overextended and pulled free of the reinforced bones.