How to care for the bones

CARE OF THE BONES In addition to the measures just mentioned to help protect the spinal disks, and precautions against accidents, proper nutrition is extremely important for bone health. Vitamin D is essential for bone production, and other vitamins are required to nourish the bone marrow. These are to be obtained in a balanced diet. Calcium, too, is vital. Most of the calcium in the body is in the bones, but calcium is also needed for muscle contraction, for heartbeat, and for blood clotting. In a remark- able automatic process, when the amount of calcium immediately avail- able for the heart and other parts of the body falls below a certain level, some of the calcium from bone is carried by the blood to these areas.

This is normal and healthy, but it underscores the need for adequate intake of calcium to maintain the bone stores. Milk contains plentiful amounts of calcium, which is one reason why it is such a basic item in the diet of growing children and in pregnant and nursing mothers. All through life there is need for adequate calcium intake, and this can be assured by a balanced diet. Calcium is contained in many food items. It is plentiful in dairy foods such as cheeses and in skim or fat-free as well as whole milk. After the menopause, bones in women need special care.   

Bones and disks

THE DISKS The spinal disks absorb the impact of body weight and movements. Normally, they serve as efficient shock absorbers for a long lifetime. But some of us give them more load or shock than they can bear-through excessive body weight, excessive or improper load lifting, and neglect of good tone in the muscles of both back and abdomen which help to maintain good posture. There is no such thing as a "slipped" disk, although you hear the term often. What has happened to the victim of a so-called slipped disk is that the disk has been crushed or has worn out and a portion of it has been extruded. The ligaments and fibrous layers of the disk have weakened, and the nucleus has been pushed out from the center into the spinal canal, compressing the nerve roots that branch from the spinal cord at this level.

The disk most commonly undergoing such herniation is the one between the fourth and fifth lumbar (lower back) vertebrae. When this disk is affected, pain is usually felt down the back of the leg and even into the side of the foot. Disk herniation can occur gradually over a period of many years of strenuous jarring activity, or it can be caused by an accident like a fall. Effective treatment for disk herniation is available. It may be conservative, relying upon removal of pressure from nerve roots, use of a firm bed or bed board, traction, and medication. In some cases, surgery may be required. The wise thing, of course, is to prevent disk problems. One sensible measure is to keep body weight at the proper level. Another is to be careful in picking up heavy weights. And very much worthwhile is the maintenance of physical fitness through regular moderate exercise and the use of special exercises (see page 89) for strengthening back and abdominal muscles. 

THE STRUCTURE AND STRENGTH OF BONE

 THE STRUCTURE AND STRENGTH OF BONE

 About one fifth of the weight of bone is water. Of the rest, about two thirds is mineral and one third organic matter. The minerals are chiefly compounds of calcium and phosphorus, with some of magnesium and other elements, while the organic matrix is chiefly a kind of protein fiber, collagen, which also is found in skin and connective tissue. The organic and inorganic components of bone along with cement- like substance are combined in a way that is sometimes compared to reinforced concrete. Bone is so strong that there are areas along the out- side of the femur, the long bone between hip and knee, which have been known to resist pressure of over 1,200 pounds per square inch.

 There are long bones like the femur (thigh bone), short ones like those in the wrist, flat ones like the shoulder blade, and irregular types like the vertebrae in the spinal column. All, however, have an outer layer of compact bone and an inner meshwork of less dense, actually porous material. Even the inner layer, sometimes called spongy because of its appearance, is remarkably strong. Far from being inert, the bones contain living cells and blood vessels. There are in fact three types of cells: the osteoblasts, which function in the construction of new bone material and repair of broken bones; the osteoclasts, which dissolve bone bits that are not required; and the osteocytes, which maintain the health of bone around them, using materials obtained from blood.

The long bones, ribs, and vertebrae are the sites, too, where the red blood cells of the body are produced. Each minute, millions of these vital elements are developed in the spongy area from red marrow, since the body requires billions and their lifetime is only a few months. Thus, the bony framework is not at all comparable to the framework of a building. It is a living framework. And while it has rigidity, it also has flexibility. Muscles are anchored to bone, and the anchoring must be strong. But there has to be movement, too. And it has been said aptly that man is a mixture of stiffness and relaxation, restriction and freedom, joints without movement and joints with great versatility.