Despite their hardness and strength, bones can suffer from injury and disease. Bone problems include fractures, osteoarthritis, and rickets. Fractures are breaks in bone, usually caused by excessive stress on bone. Fractures heal when osteoclasts form new bone. Osteoarthritis is a condition in which cartilage breaks down in joints due to wear and tear, causing joint stiffness and pain. Rickets is softening of the bones in children that occurs because bones do not have enough calcium. Rickets can lead to fractures and bowing of the leg bones.5
Support, Movement, and Protection
Some functions of the skeletal system are more readily observable than others. When we move we can feel how your bones support us, enable our movement, and protect the soft organs of our bodies. In the same way that steel beams of a building provide a framework to support its weight, the bones and cartilages of our skeletal system make up the framework that supports the rest of our bodies. Without the skeletal system, we would be a limp pile of organs, muscle, and skin. Bones facilitate our movements by serving as points of attachment for our muscles. Bones also protect internal organs from injury by covering or surrounding them. For example, our ribs protect our lungs and heart, the bones of our vertebral column (spine) protect our spinal cord, and the bones of your cranium (skull) protect our brain.6
Mineral and Fat Storage, Blood Cell Formation
On a metabolic level, bone tissue performs several critical functions. The bone tissue acts as a collecting location for a number of minerals important to the functioning of the body, specifically calcium and phosphorus. These minerals can be released back into the bloodstream to keep levels needed to support healthy processes. Calcium ions, for example, are essential for muscle contractions and are involved in the transmission of nerve impulses. Bones also serve as a site for fat storage and blood cell production. As noted above, the connective tissue that fills the interior of most bones is called bone marrow. There are two types of bone marrow: yellow bone marrow and red bone marrow. Yellow bone marrow which serves as a source of energy for other tissues of the body. Red bone marrow is where the production of blood cells takes place. Red blood cells, white blood cells, and platelets are all produced in the red bone marrow.7
Problems with Bones
An orthopedist is a doctor who specializes in diagnosing and treating disorders and injuries related to the musculoskeletal system. Some orthopedic problems can be treated with medications, exercises, braces, and other devices, but others may be best treated with surgery. While the origin of the word “orthopedics” (ortho- = “straight”; paed- = “child”), literally means “straightening of the child,” orthopedists can have patients who range from pediatric to geriatric. Orthopedists commonly treat bone and joint injuries but they also treat other bone conditions including curvature of the spine. Mostly, they are readily treated by orthopedists. As people age, accumulated spinal column injuries and diseases like osteoporosis can also lead to curvatures of the spine, hence the stooping you sometimes see in the elderly.
One interesting element of bone is that it requires load (force being applied by weight) for it to grow. Therefore, in people who are sedentary, people in anti-gravity conditions, ie. Space flight, osteoporosis becomes a large concern. It may be something to touch on with this age group because it encourages movement for loading bone and continuous growth. Some orthopedists sub-specialize in sports medicine, which addresses both simple injuries, such as a sprained ankle, and complex injuries, such as a torn rotator cuff in the shoulder. Treatment can range from exercise to surgery.8
Prosthetic Limbs
People can lose all or part of an arm or leg for many reasons. Common reasons for amputation include circulation problems from atherosclerosis or diabetes; traumatic injuries, including from traffic accidents and military combat; cancer; and birth defects. An artificial limb can sometimes replace it. The device, which is called a prosthesis, can help a patient perform daily activities such as walking, eating, or dressing. Some artificial limbs let people function nearly as well as before.
Newer materials, such as advanced plastics and carbon-fiber composites can make a prosthetic limb light, strong and realistic. Electronic technologies make today's advanced prosthetics more controllable, even capable of automatically adapting their function during certain tasks, such as gripping or walking. While new materials and technologies have certainly modernized prosthetics over the past century, the basic components of prosthetic limbs remain the same.
The pylon is the internal frame or skeleton of the prosthetic limb. The pylon must provide structural support and has traditionally been formed of metal rods. In more recent times, lighter carbon-fiber composites have been used to form the pylons. The pylons are sometimes enclosed by a cover, typically made from a foam-like material. The cover can be shaped and colored to match the recipient's skin tone to give the prosthetic limb a more lifelike appearance.
The socket is the portion of the prosthetic device that interfaces with the patient's limb stump or residual limb. The socket transmits forces from the prosthetic limb to the patient's body so it must be precisely fitted to the residual limb so that it doesn't cause irritation or damage to the skin. A soft liner is generally placed within the interior of the socket, and the patient might also wear a layer of one or more prosthetic socks for a snug fit.
The suspension system is what keeps the prosthetic limb attached to the body. The suspension mechanism can come in several different forms. For example, in the case of a harness system, straps, belts or sleeves are used to attach the prosthetic device. For some types of amputations, the prosthetic stays attached just by fitting around the shape of the residual limb. One of the most common types of suspension mechanisms relies on suction. The prosthetic limb fits snugly onto the residual limb, and an airtight seal keeps it in place.
Though most prosthetic limbs have these basic components in some form, each device is unique and designed for a specific type and level of amputation. Whether an amputation is above or below major joints, like the elbow or knee, makes a big difference in what type of prosthetic limb is required. For example, an amputation above the knee requires a prosthetic device with an artificial knee, while an amputation below the knee allows the patient to retain the use of his or her own knee.9
