The human skeleton is the internal framework of the body. It is composed of around 300 bones at birth – this decreases to 206 bones by adulthood after some bones have fused together. The bone mass in the skeleton reaches maximum density around the age of 20. The human skeleton can be divided into the axial skeleton and the appendicular skeleton. The axial skeleton is formed by the vertebral column, the rib cage, the skull and other associated bones. The appendicular skeleton, which is attached to the axial skeleton, is formed by the shoulder girdle, the pelvic girdle and the bones of the upper and lower limbs. The human skeleton performs six major functions;
- support - The skeleton provides the framework which supports the body and maintains its shape. The pelvis, associated ligaments and muscles provide a floor for the pelvic structures. Without the rib cages, costal cartilages, and intercostal muscles, the lungs would collapse.
- movement - The joints between bones allow movement, some allowing a wider range of movement than others, e.g. the ball and socket joint allows a greater range of movement than the pivot joint at the neck. Movement is powered by skeletal muscles, which are attached to the skeleton at various sites on bones. Muscles, bones, and joints provide the principal mechanics for movement, all coordinated by the nervous system.
It is believed that the reduction of human bone density in prehistoric times reduced the agility and dexterity of human movement. Shifting from hunting to agriculture has caused human bone density to reduce significantly.
- protection - The skeleton helps to protect our many vital internal organs from being damaged.
The skull protects the brain
The vertebrae protect the spinal cord.
The rib cage, spine, and sternum protect the lungs, heart and major blood vessels.
- production of blood cells - Blood cell production
The skeleton is the site of haematopoiesis, the development of blood cells that takes place in the bone marrow. In children, haematopoiesis occurs primarily in the marrow of the long bones such as the femur and tibia. In adults, it occurs mainly in the pelvis, cranium, vertebrae, and sternum.
- storage of minerals - The bone matrix can store calcium and is involved in calcium metabolism, and bone marrow can store iron in ferritin and is involved in iron metabolism. However, bones are not entirely made of calcium, but a mixture of chondroitin sulfate and hydroxyapatite, the latter making up 70% of a bone. Hydroxyapatite is in turn composed of 39.8% of calcium, 41.4% of oxygen, 18.5% of phosphorus, and 0.2% of hydrogen by mass. Chondroitin sulfate is a sugar made up primarily of oxygen and carbon.
- endocrine regulation - Bone cells release a hormone called osteocalcin, which contributes to the regulation of blood sugar (glucose) and fat deposition. Osteocalcin increases both the insulin secretion and sensitivity, in addition to boosting the number of insulin-producing cells and reducing stores of fat.
In addition to the bones, the Skeletal System consists of a network of tendons, ligaments and cartilage that connects them. Animals with internal skeletons made of bone are called vertebrates, which are actually in the minority, as 98 percent of all animals are invertebrates, meaning they do not have internal skeletons or backbones. The skeletons of adult males and females have some variation, subtle differences between sexes in the morphology of the skull, dentition, long bones, and pelvis exist. In general, female skeletal elements tend to be smaller and less robust than corresponding male elements within a given population. The human female pelvis is also different from that of males in order to facilitate child birth. Unlike most primates, human males do not have penile bones.
Unlike other living organs, bones are firm and strong, but they have their own blood, lymphatic vessels, and nerves.
There are two types of tissue inside bones:
- Compact bone: This hard and dense tissue makes up the outer layer of most bones and the main shaft of long bones, such as those in the arms and legs. Nerves and blood vessels live inside this tissue.
- Spongy bone: This tissue is made up of smaller plates filled with red bone marrow. It is found at the ends of long bones, like the head of the femur, and at the center of other bones.
Red bone marrow forms most of the blood cells in the body and helps destroy old blood cells. Another type of marrow, yellow bone marrow, resides in the central cavities of long bones. It is mostly made up of fat. However, if the body suffers large amounts of blood loss, it can convert yellow marrow to red to make more blood cells.
The skeletal system has two distinctive parts: the axial skeleton and the appendicular skeleton.
- The axial skeleton, with a total of 80 bones, consists of the vertebral column, the rib cage and the skull. The axial skeleton transmits the weight from the head, the trunk and the upper extremities down to the lower extremities at the hip joints, which help humans maintain our upright posture, the NLM noted.
- The appendicular skeleton has a total of 126 bones, and is formed by the pectoral girdles, the upper limbs, the pelvic girdle and the lower limbs, according to the NLM. Their functions are to make walking, running and other movement possible and to protect the major organs responsible for digestion, excretion and reproduction.
Other bone groups are comprised as follows:
- The skull consists of 22 separate bones that make up the cranium, the housing for the brain. Twenty-one of those bones are fused together by sutures, nearly rigid fibrous joints. The lower-most bone of the skull is the mandible, or jawbone.
- The spine, or vertebral column, is a series of irregularly shaped bones in the back that connects to the skull. At birth, humans have 33 or 34 of these bones. But bones fuse as we age, and the result is 26 separate bones in the spines of adults.
- The rib cage is made up of 12 pairs of bones that encase vital organs in the chest. The bones curve from the back at the vertebral column to the front of the body. The upper seven pairs meet with the sternum, or chest bone. The remaining five pairs are attached to each other via cartilage or do not connect.
- The muscles of the shoulders and arms include the clavicle (collarbone), scapula (shoulder blade), humerus, radius, ulna, and the bones of the wrist and hand.
- The hip bones are three sets of bones—ilia, ischia, and pubes—that fuse together as we grow older. These form the majority of the pelvis at the base of the spine as well as the socket of the hip joint. The sacrum—five fused bones and at the bottom of the spine—and the coccyx, or tailbone, make the rest of the bones in the pelvic region.
- The head of the femur, the largest and longest bone in the body, creates the other half of the hip joint and extends down to form part of the knee. It begins the bones of the leg. The other bones of the leg include the tibia, fibula, and the bones of the ankle and foot.
The most common condition that affects bones is fracture, or when a bone endures such a great impact that it breaks. Other common conditions that affect the skeletal system include:
- Osteoporosis: This is a disease in which the bones become fragile and prone to fracture.
- Leukemia: This is a cancer of the white blood cells.
- Osteopenia, osteitis deformans, and osteomalacia: Similar to osteoporosis, these are other types of bone loss.
- Scoliosis, kyphosis, and lordosis: These are abnormalities of the spinal curve.
X-rays, MRIs, bone density tests and arthroscopy are some of the primary diagnostic tools used to detect diseases and deformities of the skeletal system. Bone scans and bone marrow biopsies are used to diagnose cancer, according to the Merck Manuals.
The primary skeletal conditions are metabolic bone diseases such as osteoporosis, osteomalacia, and a few other rarer conditions. Osteoporosis is a prevalent disease, particularly among the elderly, resulting in the loss of bone tissue. In osteoporosis, bone loses calcium, becomes thinner and may disappear completely, according to Wei. Osteomalacia is a softening of the bones, according to the Mayo Clinic. It is often caused by a vitamin D deficiency and results from a defect in the bone-building process. Osteoporosis, on the other hand, develops in previously constructed bones. Arthritis is a group of more than 100 inflammatory diseases that damage joints and their surrounding structures. Arthritis can attack joints, joint capsules, the surrounding tissue, or throughout the body. It usually affects the joints of the neck, shoulders, hands, lower back, hips, or knees. “The diagnosis is suspected by a careful history and physical exam and confirmed through laboratory and imaging studies. Treatment depends on the type of arthritis,” Wei said. Also common is scoliosis, a side-to-side curve in the back or spine, often creating a pronounced "C" or "S" shape when viewed on an x-ray of the spine. This condition is typically becomes evident during adolescence, the Merck Manuals noted.
About 90 percent of people will experience lower back pain at some point in their lives, according to Dr. James Nace of LifeBridge Health. “Patients can often be helped with things such as anti-inflammatory medications, but in some cases may need treatments such as topical medications, patches or electrical stimulation.”
One of the much rarer diseases of the skeletal system is bone cancer. It may originate in the bones or spread there from another part of the body. In the United States, primary bone cancers accounts for less than 1 percent of all cancer cases, according to the American Cancer Society. Cancers that metastasize — originate from other parts of the body and then spread to the bones — are much more common than primary bone cancer.
Bone cancer is a malignancy arising in the bones and supporting structures such as cartilage, according to Dr. Robert Christie, medical oncologist and hematologist at Virginia Cancer Specialists, a practice in The U.S. Oncology Network. “Unfortunately, these bone cancers are often seen in younger patients in their 20s and 30s versus lung cancer and breast cancer which are typically diagnosed later in life.”
While leukemia is a cancer that primarily affects the blood, the skeletal system is involved as the cancer starts in the marrow of the bone. With this type of cancer, abnormal white blood cells multiply uncontrollably, affecting the production of normal white blood cells and red blood cells, according to the American Cancer Society. Bursitis is a disorder that most commonly affects the shoulder and hip joints, Nace said. It is caused by an inflammation of the bursa, small fluid-filled bags that act as lubricating surfaces for muscles to move over bones.
The skeletal system is also susceptible to breaks, strains and fractures. While bones are meant to protect the body’s vital organs, it takes about 10 to 16 pounds of pressure to break an average bone. Bones such as the skull and femur are much tougher to break.
It is often reported that more people take time off work as a result of back pain than for any other condition. This may be caused or aggravated by many factors, including poor posture, prolonged sitting, incorrect lifting of heavy loads, or psychological stress. Another problem is the so-called slipped disc. Between each pair of vertebrae are cartilage discs containing a resilient, jelly-like substance: The purpose of these discs is to act as shock absorbers, thus preventing the vertebrae from grinding together whenever we move. However, discs are vulnerable to injury. A severe jolt caused by a fall, for example, can rupture the disc’s tough envelope, permitting the enclosed jelly to ooze out. (The term ‘slipped’ disc is therefore a misnomer; herniated would be the precise definition.) The jelly-like material then presses on a nerve which results in excruciating pain. This is because the irritated nerve causes the surrounding muscles to go in to spasm; a self-protective mechanism to prevent. movement that might cause further damage. A slipped disc is best dealt with by an osteopath or chiropractor. However, regular aromatherapy massage can help during the recovery period.
Aromatherapy can also be of enormous benefit in dealing with activity injuries such as strains and sprains. One bone disorder that afflicts almost everyone to some degree is osteoporosis or ‘brittle bone’ disease. This is an age-related problem characterised by decreased bone mass and increased susceptibility to fractures. Calcium and other essential minerals are leached into the bloodstream in greater quantities and are eventually excreted. Women (especially those of European or Asian descent) are especially vulnerable to osteoporosis after menopause, for the development of the disorder is believed to be related to decreased levels of oestrogens. But since elderly men are also in the high-risk category, oestrogen deficiency is not the sole cause.
Even though heredity plays an important role in the development of osteoporosis in both men and women, there is still a great deal we can do to lessen (perhaps even prevent) the development of this debilitating disorder. Once bone is lost, however, it cannot be restored with tissue of equal strength. Nevertheless, prevention lies in the area of diet and lifestyle. Studies have shown that regular weight-bearing exercise, such as walking, cycling and climbing, increase bone mass. But such activities need to be carried out regularly for at least twenty minutes, three to five times a week. Of all the problems associated with the muscles and joints, arthritis and rheumatism are the best known, and perhaps the least understood by the medical profession.
Yet contrary to what the orthodox medics may tell you, it is possible to overcome these two potentially crippling diseases. Indeed, there are several people (and have read about many others) who have used natural therapies such as acupuncture, massage, herbal medicine, homoeopathy and dietary reform to reduce pain greatly and increase mobility in affected parts of the body. However, there is no ‘magic bullet’. Natural healing takes a great deal of time, patience and commitment. And it is for these reasons that comparatively few people give complementary healing a fair chance.
The main aim of treatment is to detoxify the system and to normalise the acid/alkaline composition of the blood (arthritis and rheumatism are associated with over-acidity). Treatment is also geared to reducing stress and increasing flexibility. This may be achieved by a combination of methods such as mineral salt baths, aromatherapy massage, aromatic compresses, gentle stretching, deep breathing and relaxation exercises, and by sticking to a predominantly alkaline diet. For example, by cutting out. or reducing to a bare minimum acid-producing foods and beverages such as pork, tea, coffee and chocolate, and by eating plenty of fresh fruits, vegetables, sprouted seeds and grains. However, no one diet is right for everyone. For instance, you may find that so-called ‘goodies’ such as apples or green grapes exacerbate your own particular symptoms. Therefore, it is advisable to consult an holistic nutritionist who will devise a personalised dietary plan.
Although essential oils cannot heal bone disorders like osteoporosis, they can help to alleviate the discomfort of arthritic and rteumat1c conditions. The principal actions of essential oils which help in this way are as follows:
Anti-inflammatories: As well as helping to rescue pain and inflammation in arthritic joints, such essences also help reduce swelling around injuries, for example chamomile (German and Roman), galbanum, lavender.
Anti-rheumatics: Many essences have the reputation or preventing and relieving rheumatic problems, for example angelica, coriander; juniper.
Depuratives: These help to detoxify the system of metabolic wastes, for example juniper, lemon, rose otto.
Rubefacients: By stimulating the periphery circulation, such essences increase the blood supply to the affected area which in tum relieves congestion and inflammation, for example black pepper, ginger, rosemary.
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