Great force is required to fracture the sternum.
The main danger of such an injury is the possibility that the broken bone may be driven inwards, damaging the heart, which lies behind the sternum.
Great force is required to fracture the sternum.
The main danger of such an injury is the possibility that the broken bone may be driven inwards, damaging the heart, which lies behind the sternum.
The next 2 or 3 pairs of “false ribs” connect indirectly to the sternum by means of cartilage attached to the cartilage of the ribs above.
Between and attached to the ribs are thin sheets of muscle (intercostal muscles) that act during breathing.
The spaces between the ribs also contain nerves and blood vessels.... rib
Structure of bone Bone is composed partly of ?brous tissue, partly of bone matrix comprising phosphate and carbonate of lime, intimately mixed together. The bones of a child are about two-thirds ?brous tissue, whilst those of the aged contain one-third; the toughness of the former and the brittleness of the latter are therefore evident.
The shafts of the limb bones are composed of dense bone, the bone being a hard tube surrounded by a membrane (the periosteum) and enclosing a fatty substance (the BONE MARROW); and of cancellous bone, which forms the short bones and the ends of long bones, in which a ?ne lace-work of bone ?lls up the whole interior, enclosing marrow in its meshes. The marrow of the smaller bones is of great importance. It is red in colour, and in it red blood corpuscles are formed. Even the densest bone is tunnelled by ?ne canals (Haversian canals) in which run small blood vessels, nerves and lymphatics, for the maintenance and repair of the bone. Around these Haversian canals the bone is arranged in circular plates called lamellae, the lamellae being separated from one another by clefts, known as lacunae, in which single bone-cells are contained. Even the lamellae are pierced by ?ne tubes known as canaliculi lodging processes of these cells. Each lamella is composed of very ?ne interlacing ?bres.
GROWTH OF BONES Bones grow in thickness from the ?brous tissue and lime salts laid down by cells in their substance. The long bones grow in length from a plate of cartilage (epiphyseal cartilage) which runs across the bone about 1·5 cm or more from its ends, and which on one surface is also constantly forming bone until the bone ceases to lengthen at about the age of 16 or 18. Epiphyseal injury in children may lead to diminished growth of the limb.
REPAIR OF BONE is e?ected by cells of microscopic size, some called osteoblasts, elaborating the materials brought by the blood and laying down strands of ?brous tissue, between which bone earth is later deposited; while other cells, known as osteoclasts, dissolve and break up dead or damaged bone. When a fracture has occurred, and the broken ends have been brought into contact, these are surrounded by a mass of blood at ?rst; this is partly absorbed and partly organised by these cells, ?rst into ?brous tissue and later into bone. The mass surrounding the fractured ends is called the callus, and for some months it forms a distinct thickening which is gradually smoothed away, leaving the bone as before the fracture. If the ends have not been brought accurately into contact, a permanent thickening results.
VARIETIES OF BONES Apart from the structural varieties, bones fall into four classes: (a) long bones like those of the limbs; (b) short bones composed of cancellous tissue, like those of the wrist and the ankle; (c) ?at bones like those of the skull; (d) irregular bones like those of the face or the vertebrae of the spinal column (backbone).
The skeleton consists of more than 200 bones. It is divided into an axial part, comprising the skull, the vertebral column, the ribs with their cartilages, and the breastbone; and an appendicular portion comprising the four limbs. The hyoid bone in the neck, together with the cartilages protecting the larynx and windpipe, may be described as the visceral skeleton.
AXIAL SKELETON The skull consists of the cranium, which has eight bones, viz. occipital, two parietal, two temporal, one frontal, ethmoid, and sphenoid; and of the face, which has 14 bones, viz. two maxillae or upper jaw-bones, one mandible or lower jaw-bone, two malar or cheek bones, two nasal, two lacrimal, two turbinal, two palate bones, and one vomer bone. (For further details, see SKULL.) The vertebral column consists of seven vertebrae in the cervical or neck region, 12 dorsal vertebrae, ?ve vertebrae in the lumbar or loin region, the sacrum or sacral bone (a mass formed of ?ve vertebrae fused together and forming the back part of the pelvis, which is closed at the sides by the haunch-bones), and ?nally the coccyx (four small vertebrae representing the tail of lower animals). The vertebral column has four curves: the ?rst forwards in the neck, the second backwards in the dorsal region, the third forwards in the loins, and the lowest, involving the sacrum and coccyx, backwards. These are associated with the erect attitude, develop after a child learns to walk, and have the e?ect of diminishing jars and shocks before these reach internal organs. This is aided still further by discs of cartilage placed between each pair of vertebrae. Each vertebra has a solid part, the body in front, and behind this a ring of bone, the series of rings one above another forming a bony canal up which runs the spinal cord to pass through an opening in the skull at the upper end of the canal and there join the brain. (For further details, see SPINAL COLUMN.) The ribs – 12 in number, on each side – are attached behind to the 12 dorsal vertebrae, while in front they end a few inches away from the breastbone, but are continued forwards by cartilages. Of these the upper seven reach the breastbone, these ribs being called true ribs; the next three are joined each to the cartilage above it, while the last two have their ends free and are called ?oating ribs. The breastbone, or sternum, is shaped something like a short sword, about 15 cm (6 inches) long, and rather over 2·5 cm (1 inch) wide.
APPENDICULAR SKELETON The upper limb consists of the shoulder region and three segments – the upper arm, the forearm, and the wrist with the hand, separated from each other by joints. In the shoulder lie the clavicle or collar-bone (which is immediately beneath the skin, and forms a prominent object on the front of the neck), and the scapula or shoulder-blade behind the chest. In the upper arm is a single bone, the humerus. In the forearm are two bones, the radius and ulna; the radius, in the movements of alternately turning the hand palm up and back up (called supination and pronation respectively), rotating around the ulna, which remains ?xed. In the carpus or wrist are eight small bones: the scaphoid, lunate, triquetral, pisiform, trapezium, trapezoid, capitate and hamate. In the hand proper are ?ve bones called metacarpals, upon which are set the four ?ngers, each containing the three bones known as phalanges, and the thumb with two phalanges.
The lower limb consists similarly of the region of the hip-bone and three segments – the thigh, the leg and the foot. The hip-bone is a large ?at bone made up of three – the ilium, the ischium and the pubis – fused together, and forms the side of the pelvis or basin which encloses some of the abdominal organs. The thigh contains the femur, and the leg contains two bones – the tibia and ?bula. In the tarsus are seven bones: the talus (which forms part of the ankle joint); the calcaneus or heel-bone; the navicular; the lateral, intermediate and medial cuneiforms; and the cuboid. These bones are so shaped as to form a distinct arch in the foot both from before back and from side to side. Finally, as in the hand, there are ?ve metatarsals and 14 phalanges, of which the great toe has two, the other toes three each.
Besides these named bones there are others sometimes found in sinews, called sesamoid bones, while the numbers of the regular bones may be increased by extra ribs or diminished by the fusion together of two or more bones.... bone
Contents The trachea divides into right and left main bronchi which go to the two LUNGS. The left lung is slightly smaller than the right. The right has three lobes (upper, middle and lower) and the left lung has two lobes (upper and lower). Each lung is covered by two thin membranes lubricated by a thin layer of ?uid. These are the pleura; similar structures cover the heart (pericardium). The heart lies in the middle, displaced slightly to the left. The oesophagus passes right through the chest to enter the stomach just below the diaphragm. Various nerves, blood vessels and lymph channels run through the thorax. The thoracic duct is the main lymphatic drainage channel emptying into a vein on the left side of the root of the neck. (For diseases affecting the chest and its contents, see HEART, DISEASES OF; LUNGS, DISEASES OF; CHEST, DEFORMITIES OF.)... chest
Barrel chest is found in long-standing ASTHMA or chronic BRONCHITIS and EMPHYSEMA, when the lungs are chronically enlarged. The anterio-posterior dimension of the chest is increased and the ribs are near horizontal. In this position they can produce little further expansion of the chest, and breathing often relies on accessory muscles in the neck lifting up the whole thoracic cage on inspiration.
Pigeon chest is one in which the cross-section of the chest becomes triangular with the sternum forming a sort of keel in front. It may be related to breathing problems in early life.
Rickety chest is uncommon now and is caused by RICKETS in early life. There is a hollow down each side caused by the pull of muscles on the softer ribs in childhood. The line of knobs produced on each side where the ribs join their costal cartilages is known as the rickety rosary.
Pectus excavatum, or funnel chest, is quite a common abnormality where the central tendon of the diaphragm seems to be too short so that the lower part of the sternum is displaced inwards and the lower ribs are prominent. When severe, it may displace the heart further to the left side.
Local abnormalities in the shape of the chest occur when there is a deformity in the spine such as scoliosis which alters the angles of the ribs. The chest wall may be locally ?attened when the underlying lung is reduced in size locally over a prolonged period. (See SPINE AND SPINAL CORD, DISEASES AND INJURIES OF.) This may be seen over a scarred area of lung such as that observed in pulmonary TUBERCULOSIS.... chest, deformities of
Costochondritis is inflammation affecting the cartilage between the ribs and the sternum (breastbone).... chondritis
Atherosclerosis can be the forerunner of degenerative heart and kidney disease, with rise in blood pressure.
A study of Australian ’flu epidemic diseases revealed influenza as a major cause of cardiovascular disease and in particular, atherosclerosis.
Causes. Excessive smoking and alcohol, fatty foods, hereditary weakness, stress and emotional tension that release excessive adrenalin into the bloodstream. Toxic effects of environmental poisons (diesel fumes). Fevers.
Symptoms. Cold hands and feet, headache, giddiness. Diminished mental ability due to thickening of arteries in the brain. Pain on exertion, breathlessness and fatigue. Diagnosis of atheroma of main arteries: by placing stethoscope over second right intercostal space, half inch from the sternum, the second aortic sound will be pronounced.
Treatment. Surface vasodilators, Cardioactives. Anti-cholesterols.
Alternatives. Teas. To lower cholesterol levels and shrink hardened plaque: Alfalfa, Chamomile, Borage, Olive leaves, Mint, Nettles, Marigold, Garlic, Lime flowers, Yarrow, Horsetail, Hawthorn, Ginkgo, Orange Tree leaves, Meadowsweet, Eucalyptus leaves, Ispaghula, Bromelain. Rutin (Buckwheat tea).
Artichoke leaves. Spanish traditional. 2 teaspoons to each cup of water; simmer 2 minutes. Drink cold: 1 cup 2-3 times daily.
Mistletoe leaves. 1-2 teaspoons to each cup cold water steeped 8 hours (overnight). Half-1 cup thrice daily.
Tablets, or capsules. Garlic, Mistletoe, Poke root, Rutin, Hawthorn, Motherwort, Ginkgo, Bamboo gum. Liquid Extracts. Mix Hawthorn 2; Mistletoe 1; Barberry 1; Rutin 1; Poke root half. Dose: 30-60 drops thrice daily.
Tinctures. Mix: Hawthorn 2; Cactus flowers 2; Mistletoe 1; Capsicum half. Dose: 1-2 teaspoons thrice daily in water before meals.
Powders. Mix equal parts: Bamboo gum, Hawthorn, Mistletoe, Rutin, Ginger. Fill 00 capsules. Dose: 2-4 capsules, or quarter to half a teaspoon (375-750mg) thrice daily before meals.
Threatened stroke. Tincture Arnica BPC (1949): 3-5 drops in water morning and evening. Practitioner only.
Evening Primrose oil. Favourable results reported. (Maxepa)
Diet. Vegetarian. Low fat. Low salt. High fibre. Lecithin, polyunsaturated oils, artichokes, oily fish (see entry). Linseed on breakfast cereal. Garlic at meals, or Garlic tablets or capsules at night to reduce cholesterol.
Vitamins. A, B-complex, B6, B12, C (2g), E (400iu), daily.
Minerals. Chromium, Iodine, Potassium, Selenium, Magnesium, Manganese, Zinc.
“A man is as old as his arteries” – Thomas Sydenham, 17th century physician.
“A man’s arteries are as old as he makes them” – Robert Bell MD, 19th century physician. ... atherosclerosis
cavities; it may be red or yellow. Red bone marrow is present in all bones at birth and is the factory for most of the blood cells. During the teens, red bone marrow is gradually replaced in some bones by less active yellow marrow. In adults, red marrow is confined chiefly to the spine, sternum, (breastbone), ribs, pelvis (hip-bones), scapulae (shoulderblades), clavicles (collarbones), and bones of the skull.
Stem cells within the red marrow are stimulated to form blood cells by the hormone erythropoietin.
Yellow marrow is composed mainly of connective tissue and fat.
If the body needs to increase its rate of blood formation, some of the yellow marrow will be replaced by red.
Sometimes marrow fails to produce sufficient numbers of normal blood cells, as occurs in aplastic anaemia (see anaemia, aplastic) or when marrow has been displaced by tumour cells.
In other cases, marrow may overproduce certain blood cells, as occurs in polycythaemia and leukaemia.... bone imaging
and plays an important role in breathing. There are openings in the diaphragm for the oesophagus and major nerves and blood vessels. To inhale, the diaphragm’s muscle fibres contract, pulling the whole diaphragm downwards and drawing air into the lungs. (See also breathing.)... diaphragm muscle
Such joints occur between the vertebrae; between the pubic bones at the front of the pelvis; and between the upper and middle parts of the sternum.... symphysis
There are 2 types of thoracotomy: lateral and anterior. In a lateral thoracotomy the chest is opened between 2 ribs to provide access to the lungs, major blood vessels, and the oesophagus. In an anterior thoracotomy, an incision down the sternum (breastbone) provides access to the heart and the coronary arteries.... thoracotomy
surrounding tissues. Radionuclide scanning detects areas throughout the skeleton in which there is high bone-cell activity. This type of scanning and on the presence of cells foreign to the marrow.
It is useful in the diagnosis of many blood disorders, including leukaemia and anaemia.
It can also show whether bone marrow has been invaded by lymphoma or cells from other tumours.... bone marrow biopsy
It is usually due to a viral infection.
Bacterial infection of the airways may occur as a complication.
Smokers, babies, elderly people, and those with lung disease are particularly susceptible.
The main symptoms are wheezing, shortness of breath, and a cough that produces yellow or green sputum.
There may also be pain behind the sternum (breastbone) and fever.
Symptoms may be relieved by drinking plenty of fluids and inhaling steam or using a humidifier.
Most cases clear up without further treatment, but acute bronchitis may be serious in people who already have lung damage.... bronchitis, acute
wall. In Tietze’s syndrome, inflammation at the junctions of the rib cartilages causes pain on the front of the chest wall.
Pain within the chest may be caused by pleurisy, as a result of bronchitis, pneumonia, or, rarely, pulmonary embolism. Cancerous tumours of the lung (see lung cancer; mesothelioma) may cause pain as they grow and press on the pleura and ribs. Acid reflux may lead to heartburn, a burning pain behind the sternum. The common heart disorder angina pectoris causes pain in the centre of the chest that may spread outwards to the throat, jaw, or arms. Myocardial infarction (heart attack) and acute pericarditis both also produce severe pain in the centre of the chest. Mitral valve prolapse may cause sharp chest pain, usually on the left side. Chest pain may also be a result of anxiety and emotional stress (see hyperventilation; panic attack).... chest pain
The thymus lies behind the sternum and consists of 2 lobes that join in front of the trachea.
Each lobe is made of lymphoid tissue consisting of lymphocytes, epithelium, and fat.
The thymus conditions lymphocytes to become T-cells.
It plays a part in the immune response until puberty, gradually enlarging during this time.
After puberty, it shrinks, but some glandular tissue remains until middle-age.... thymus
The superior vena cava starts at the top of the chest, close to the sternum, and passes down through the pericardium before connecting to the right atrium. It collects blood from the upper trunk, head, neck, and arms. The inferior vena cava starts in the lower abdomen and travels upwards in front of the spine, behind the liver, and through the diaphragm before joining the right atrium. It collects blood from the legs, pelvic organs, liver, and kidneys.... vena cava