The bone is a rigid structure of connective tissue interlaced with nerves and blood vessels hardened by deposits of (chiefly) calcium phosphate.
The entire bone is sheathed in a tough tissue called the periosteum. Babies’ bones are pliable and contain a high proportion of cartilage, which is gradually replaced by more rigid bone tissue.
In adults, each bone has a very dense outer layer with a high content of calcium. Under this layer, the structure is spongy, with pores and cavities of various sizes.
Bones are the source of vital constituents of blood. They are the storehouse from which the calcium in Blood Plasma is obtained. The pores and cavities—at each knob-like end (epiphysis) of the jointed bones, in the ribs, the skull, the vertebrae, and the numerous short bones of the hands and feet—are filled with red marrow.
Red marrow consists largely of blood corpuscles in all stages of development. About 5 million mature red blood cells (Erythrocytes) are produced and released into the bloodstream every second. The blood platelets, which are essential for Blood Clot formation, and the white blood cells (Leukocytes), which protect the body against infections, are also formed in the red marrow.
The shafts (middle sections) of the long bones of the arms and legs are hollow and filled with yellow marrow. Yellow marrow is a fatty substance whose function is not known.
Bones are hinged and held together by Ligaments to form the Skeletal System. The system provides support, mechanical leverage for movement, and protection. The flat bones (skull and ribs) protect the delicate tissues of the brain and the lungs.
The long bones move on interlocking joints that are lined with cartilage. In childhood, the shafts of the long bones are separated from the epiphysis at each end by a layer of cartilage. Growth of the bone takes place at this point until adult size is reached.
Then shaft and the epiphysis fuse together. In old age, the bones become increasingly brittle.
There are relatively few diseases that directly involve the bones. Arthritis, for example, is a disease of the joints rather than the bones, although a person with arthritis may complain that his bones ache.
Conditions outside the bone may sometimes lead to deformed or stunted bone growth in children. For example, clubfoot and congenital hip dislocation are birth defects that can lead to bone deformity if not corrected.
A limping gait or any other sign of abnormality in a child’s arms or legs calls for a visit to the doctor.
The following are the major types of bone diseases:
This deformity, also known as Talipes, is present at birth. If it is not treated early, it may require surgery. However, when medical attention is sought promptly, the condition may be corrected by relatively simple measures.
At the time a child begins to walk, this condition reveals itself by a limp. This is one of many good reasons that babies should have regular checkups. The doctor will check for excessive tightness of the hips when pushing the baby’s legs apart.
If such tightness is found, the doctor may recommend X-raying the hip. The dislocation grows worse if neglected, and may require extensive surgery. When treatment is begun as soon as the condition becomes apparent—if possible, even before the child begins walking—there is good hope of correction without surgery.
This disease is called by the first name when it occurs in children; by the second, in adults. The bones do not harden normally, due to lack of calcium and phosphorous, and may become deformed, as with Bowleg. The disease is frequently relieved by means of a high-calcium diet and vitamin D
This disease, also known as osteitis deformans, usually strike the middle-aged. Typically, the bones in the leg, skull, or spine become overgrown and deformed by deposits of calcium. The cause is not known. The condition may develop so slowly that it is hardly noticed. Pain is controlled by various types of treatment, including the use of vitamin C and D, calcium, and aspirin. Sodium fluoride may arrest the spread of the disorder.
In this condition the bones become porous and brittle. The first sign is often a fracture produced by a minor jolt. Poor nutrition and inadequate blood supply to the bone are two of many possible causes; the treatment varies with the cause.
In time, most old persons suffer from osteoporosis to some degrees. Estrogens may be required in women after menopause to control osteoporosis.
This disease occurs in both acute and chronic forms. It is an infection of the bone and is produced by bacteria. Osteomyelitis most frequently strikes younger persons and usually involves the arms and legs. Antibiotics very often can cure acute osteomyelitis if administered soon after the onset of the disease. Methods in addition to antibiotics must be used to cure the chronic form
Another name for this disease is tuberculosis of the spine. It is marked by inflammation or destruction (carries) of the spinal vertebrae and is usually produced by a germ from infected cows. Pasteurization of milk has made Pott’s disease relatively uncommon
Sources and References
Reader’s Digest Family Health Guide and Medical Encyclopedia
Microbiology of Acute and Chronic Osteomyelitis and Antibiotic Treatment by Harry Dym and Joseph Zeidan
Menopausal Osteoporosis: Screening, Prevention and Treatment by Eu-Leong Yong and Susan Logan