the bones and muscles (common question)
I know that bones are hard and strong and that they support the body, bu I`m not sure what they are made of. Can you tell me?
Bone tissue is composed of living cells intermixed with minerals, mainly calcium and phosphorus, which give bone its characteristic hardness. Bones vary in shape and size-from the long bones of the limbs to the short bones of the hands and feet; there are also flat bones, such as the breastbone and skull bones, and irregular bones, such as the vetebrae. In adults, most bones ate made up of two types of tissue: hard comppact bone on the outside and porous spongy bone on the inside. In a long bone like the femur, or thighbone, the shaft consist mostly of compact bone; it is hollow and filled with fat called yellow marrow. The bulging ends of the bone consist primarily spongy bone, surrounded by a thin outer layer of compact bone. The spongy bone contains red marrow, which manufactures the blood cells. Most bone surfaces are covered with a dense fibrpous membrane, called the periosteum. Blood vessels and nerve fibres pass into the spongy interior of a bone through small channels in the hard outer layer.
It`s hard to imagine bone as living, growing tissue. How do bones grow?
Bones grow in their own unique way: the process begins with the formation of new cells. These cells then produce and surround themselves with a special organic material that forms a kind of matrix. Calcium salts are deposited in this framework and gradually harden it. Bones begin forming as warly asa two months after conception and continue growing until the age of about 16 in girls and 18 in boys. Although the final hardening of the breastbone occurs at about 25 years old, the strength and calcium content of the bones keep increasing until 35 or so. Bone remodelling, the breaking doen and replacement of bone tisue, continiues throughout most of life. Bone form in the foetus in two ways. Those at the top of the skull begin growing within a membrane of soft connective tissue. Most bones, however, start off as cartilage `models`. The models are similar in shape to the true bones that will eventually replace them, but are more pliable and better suited to the very rapid growth before birth. Each cartilage model is gradually replaced by bone tissue. In a long bone, the process begins in the centre of the shaft and at both ends. Eventually only a thin layer of cartilage, called a growth palte, remains between the shaft and each end. By continuing to form new layers of cartilage that are then replaced by bone, these plates make bone growth possible. When the plates stop forming cartilage, growth stops.
What did my doctor mean when he referred recently to my son`s bone age?
Duriong growth, the cartilage layers near the ends of the long bones-the growth plates-thin out at a predictable rate, and eventually disappear when growth ceases. Your doctor can determine the thickness of your son`s growth plates through X-rays, and thus determine his bone age. In general, bone age should match chronological age, although bone growth rate does vary from child to child. A major difference between the two can signal a harmonal problem.
It is possible for a bone to bruise?
Yes, it is. A sharp blow or a bad fall can sometimes cause bleeding just beneath the periosteum, the fibrous membrane that covers most bone surfaces and which contains blood vessels and nerves. Bone bruises are painful, but they usually heal within a few days. If the pain persists, or gets worse with activity, consult your doctor. An X-ray may be necessary to distinguish a bone bruise from a fracture.
What is the difference between a simple and a compound fracture?
All bone fracture are the result of severe trauma, whether from a fall, a violent blow or some other source.In a simple fracture, the bone is cracked or broken, but the surrounding tissues are not seriously damaged, and the skin isn`t broken. In a compound fracture, surrounding damage is often extensive, and the broken bone may protrude through neighbouring tissue and the skin. In compound fractures the danger of infection occuring is always present, and surgical treatment is necessary in most cases.Rest, and perhaps a splint or an arm sling, may suffice to treat some minor fractures. In more severe cases, the pieces of broken bone will have to be realigned. Depending on the severity of the fracture, this may or may not involve surgically opening the site of the fracture.Once the bone has been realigned, it must be immobilised either by a cast, traction or an internal device such as a pin a or a plate.
What are joints, and how are they constructed?
A joint is the structure that connects any two or more bones. Although they allow no movement, the fibrous connections that join the bones of the skull are joints, but it is the movable variety that are more usually thought of as such. Bones are held together at a joint by tough, fibrous bands called ligaments; the ends of bones are covered with smooth cartilage that provides a low-friction surface for movement. The joint space is lined with a layer of tissue, called the synovium, which produces a fluid that lubricates the joint and nourishes the cartilage. Major joints include the shoulders, elbows, wrists, hips, knees, ankles and jaw; there are also many small joints in the hands and feet and between the vertebrae of the spine. Different types of joints allow different types of movement. hinge joints, such as those at the fingers, elbows, and knees, permit back and forth motion in one plane. A ball-and-socket joint, such as the hip or shoulder joint, allows sideways and rotary, as well as back and forth, motion.
I have been cracking my knuckles for years. My wife says this habit will eventually cause arthritis. Is she right?
The biggest problem with knuckle cracking seems to be the annoyance it causes other people. Doctors are not exactly sure what produces the cracking sound, but there doesn`t appear to be a connection between chronic knucklecracking and the development of arthristis or any other physical problem.
My son dislocated his shoulder while playing football. What is a dislocation?
A dislocation is a displacement of a bone from its normal position at a joint. It is usually caused by a powerful blow or injury that tears the ligaments holding the bones in place. A common result of contact sports, dislocations can occur at almost any joint. Symptoms are severe pain, rapid swelling, discoloration and immobility; the joint also looks misshapen. For a dislocation to heal properly, the bone must be repositioned by a doctor (this may have to be done under an anaesthetic), then immobilised, possibly with splints.
What`s the difference between a tendon and ligament?
Tendons are thin, though, relatively inelastic bands of tissue that attach muscles to bones and direct their motions. Ligaments are bands of strong but elastic tissue that keep adjacent bones together and in place. Both ligaments and tendons can be injured when excessive demands are made upon them.
A friend of mine who likes to play cricket says that he has tendinitis of the shoulder. What is this condition, and how os ot treated?
Tendinitis is an inflammation of one of the many tendons in the body. It can be caused by overworking or otherwise injuring a tendon, or by muscles that are so tight that they pull on a tendon even at rest. Often the inflammation involves also the synovial sheath which protects the tendon and allows it to slide easily over a bony or joint surface, a condition known as tenosynovitis. Tendinitis can strike wherever a tendon links muscle to bone, but it is most common in the wrist, elbow (tennis elbow), back of the foot, shoulders and knees.The symptoms of tendinitis are localised soreness, swelling and restriction of movement. The first line of treatment is to rest the affected area. Applying an ice pack and taking aspirin or ibuprofen can help in reducing the pain and swelling. In more severe cases, prescription medications may be ordered by the doctor. Once the pain has subsided, the objective is to provent stiffness while being careful not to aggravate the original condition. This can be accomplished with slow, gentle stretching exercises in which the affected limb or joint is extended as far as possible with out pain and held there for at least 20 seconds. It is important not to allow the area to become immobilised through disuse. If the pain or stiffness doesn`t improve within a week, a doctor should be consulted.
What is a sprain, and how can I distinguish it from tendinitis?
A sprain is a partial tear in the ligaments that hold bones together at a joint. Sprains are most common in the ankles, knees ad fingers, but they can occur in other joints as well. The symptoms of a mild sprain are not very different from those of tendinitis; both conditions cause localised soreness and tenderness. With tendinitis, however, symptoms usually develop slowly, over a period of several days, and you will probably be able to put weight on the affected aea right away (even though the condition wll worsen without rest). Sprains, on the other hand, are nearly always the immediate result of a direct injury. They are often more incapacitating in the short term, are usually accompanied by a bruise, and may take longer to heal. A severe sprain, in which ligaments are completely torn, requires prompt medical care and may take months to heal.
Why are my muscle often sore in the morning?
I developed a severe pain in my calf muscle during an aerobics class. My doctor said I had a pulled muscle. Is this the same as a ruptured muscle?
Pulled and ruptured muscles are both commonly caused by overexertion, but there is a significant difference between them. When a muscle is overstretch, particularly by making a sudden movement, some of its fibres may tear, causing pain, swelling and weakness. This is called a pulled muscle, a common injury among athletes who have not warm up sufficiently. Pulled muscles usually heal quickly and uneventfully.A muscle is said to be ruptured when there is complete or partial separation of the muscle from the bone. A ruptured muscle has little or no strength and may require surgery to repair the damage.
Is whiplash a real condition, and if so, what is it?
Despite its reputation as an insurance ploy, whiplash is real. It is a common description of what happen, often in a car accident, when the neck is subjected to a sudden jolt. The head is thrown vionlently forwards, then jerked back; pain and stiffness are the result, sometimes lasting for long periods. In severe accidents there may be rapture of the spinal cord itself, leading to qiadriplegia or even death.The injuries sustained are most likely to be tears or sprains in the muscles and ligaments around the cervival vertebrae. The damage may require several weeks to heal, during which time the neck should be supported by a padded collar. Muscle spasm and pain may persist even after the initial injuries have heald.Rest, moderate applications of heat and massage can help to relieve the soreness and stiffness. Pain relievers and muscle relaxants can help in some cases, but reliance on such drugs may lead to dependency problems. Emotional stress seems to hinder the healing process, perhaps because the neck muscles remain tense. As a result, anyone recovering from a whiplash injury should try to relax and avoid stressful situations.
Over the weekend, I played outfield in a club cricket match. Now I can barely lift my arm. Could this be bursitis?
It could be. Bursitis is an inflammation of one of the bursae, thr sacs filled with lubricating fluid situated between bones, or between tendons and bones, to reduce friction. Injury, infection or long-term wear and tear are common causes, but flare-ups can also occur for no identifiable reason. Bursitis is characterised by localised pain and swealling, and is common in the knee ( housemaid`s knee), the elbows (student`s elbow), the shoulders, the hips, the heel of the foot and the base of the big toe. In your case, you probably irritated the bursa in the shoulder of your throwing arm. Try to rest your arm and shoulder; use a splint or sling, if necessary, for support; take aspirin or paracetamol and apply an ice pack for the pain. If you do not feel better after three or four days, or if movement becaomes more difficult, call your doctor. In severe cases of bursitis, prescription drugs may be needed; if there is extreme swealling, your doctor may anaesthetise the area, drain the bursa and inject a drug into the empty sac.
What can I do to alleviate the pain of a pulled muscle?
First of all you should stop the activity that may have caused the injury, apply ice to the affected muscle and elevate it to prevent swelling, then rest the muscle until the pain subsides, usually within a few days. If the pain and swelling are severe you should see your doctor. If you must move around with a pulled leg muscle, try bandaging the area for support or using crutches to avoid further damage. After a severly pu;;ed muscle has healed, it should be stretched and strengthened through physiotherapy before your return to your usual activities.
My friend says that hernias are really a muscle problem. Is he right?
In a sens he is. A hernia is a protrusion af all or part of an organ through a weak spot in the muscle or other tissue that contains it. In a common form of hernisa, a part of the intestine or some of the fat that covers it squeezes through a gap in the muscles of the abdominal wall-the sheet of muscles of the front and sides of the abdomen that keeps the abdominal organs in place. The muscle weakness that cause a hernia may be congenital, or it may result from strain or poor muscle tone. In the early stages, the only sign may be a bulge. Hernias are sometimes accompanied by tenderness at the site of the bulge and by a feeling of heaviness.Of the more common types of hernia, men are mote prone to inguinal hernias, in which the abdominal organs squeeze through the abdominal wall just above the groin crease, making quite a large bulge. Women, particularly if overweight, tend to have femoral gernias, which make a small bulge just below the groin crease; in some cases there is no swelling at all. Hiatus hernias occur in the diaphragm.Hernias can be dangerous. The trapping of a piece of the intestine by the herniated muscle can prevent the bowel from clearing properly. In a more serious from clearing properly. In a more serious complication, the flow of blood to the affected section of intestine may be cut off, causing gangrene, or tissue death.Surgery is the best remedy for abdominal hernias. The operation, in which the protruding tissue is pushed back in place and the muscle wall repaired, is fairly simple, and usually tkaes about an hour.
the bones and muscles (common questions)
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