The adult human body contains roughly 206 bones, both fused and individual, which are supported by a system of ligaments, tendons, muscles and cartilage. Together, this miracle of calcium and tissue allows us to run, jump, climb and even thread a needle or operate a computer via its keyboard. Without it, we would be less than slugs, but we rarely think about bones until we break one, or until time forces us to consider the combined effects of gravity and age.

No doctor's or orthopedic surgeon's office can be considered complete without a Skeletal System chart, which shows the bones in the human body from both the front and rear. Diagrams within the chart also display and describe such skeletal features as the bones of the inner ear, important in maintaining balance, and the bones of the female pelvis, integral to gestation and birth. In addition, a complete diagram of the spinal column shows how attached bones of the neck, thorax and lower back maintain the curvature needed for this balancing act. Each bone is listed with its anatomical (and common) name, enabling doctors, surgeons and teachers to explain this complex miracle of upright stature to patients and students.

Unfortunately, as we age - or if we have indulged in heavy physical work or extreme sports - bones undergo wear and tear, leading to inflammation of joints, which can cause swelling, pain and stiffness. Also known as degenerative arthritis, this condition can lead to complete debilitation if not treated. The Understanding Osteoarthritis is a superb tool doctors can use to explain not only the mechanics of a healthy joint, but what happens when these joints "wear out", and where problems are most likely to occur. Along with explanations of nutrient exchange which keeps bones strong, and an explanation of articular cartilage, the strong, elastic tissue that covers the ends of bones in joints and enables them to move smoothly over one another. Different sections also describe and explain the symptoms, risk factors and possible treatment options for osteoarthritis, including diet and lifestyle changes.

The Understanding Osteoporosis chart, which explains bone loss and "brittle bone" for the 28 million Americans (not all of them women) suffering from this age-related disease, is another essential for doctor's offices. Unchecked, osteoporosis can lead to serious health consequences like vertebral or hip fractures that leave the elderly dependent on nursing homes or permanent care. By demonstrating and explaining the bone growth and bone density loss cycles, this chart also enables physicians to promote early treatment for older women most at risk for osteoporosis (namely those females under 130 pounds of Caucasian and Asian descent who smoke or do not get sufficient exercise), and suggests dietary and lifestyle changes that can preserve existing bone

A final chart, The Musculoskeletal System, is a good, all-purpose tool for demonstrating how muscles support bones. Additional diagrams detail the vertebral column and the nature of a synovial joint. Each bone and muscle is fully labeled, giving orthopedic surgeons a handy reference to explain to their patients the need for lifestyle and dietary changes as age begins its inevitable attack on human bone.