Bone marrow transplant Health Dictionary

The framework upon which the rest of the body is built up. The bones are generally called the skeleton, though this term also includes the cartilages which join the ribs to the breastbone, protect the larynx, etc.

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

See BONE TRANSPLANT.... bone graft

Brittle Bone Disease is another name for OSTEOGENESIS IMPERFECTA.... brittle bone disease

Bone marrow is the soft substance occupying the interior of bones. It is the site of formation of ERYTHROCYTES, granular LEUCOCYTES and PLATELETS.... bone marrow

Bone is not an inert sca?olding for the human body. It is a living, dynamic organ, being continuously remodelled in response to external mechanical and chemical in?uences and acting as a large reservoir for calcium and phosphate. It is as susceptible to disease as any other organ, but responds in a way rather di?erent from the rest of the body.

Bone fractures These occur when there is a break in the continuity of the bone. This happens either as a result of violence or because the bone is unhealthy and unable to withstand normal stresses.

SIMPLE FRACTURES Fractures where the skin remains intact or merely grazed. COMPOUND FRACTURES have at least one wound which is in communication with the fracture, meaning that bacteria can enter the fracture site and cause infection. A compound fracture is also more serious than a simple fracture because there is greater potential for blood loss. Compound fractures usually need hospital admission, antibiotics and careful reduction of the fracture. Debridement (cleaning and excising dead tissue) in a sterile theatre may also be necessary.

The type of fracture depends on the force which has caused it. Direct violence occurs when an object hits the bone, often causing a transverse break – which means the break runs horizontally across the bone. Indirect violence occurs when a twisting injury to the ankle, for example, breaks the calf-bone (the tibia) higher up. The break may be more oblique. A fall on the outstretched hand may cause a break at the wrist, in the humerus or at the collar-bone depending on the force of impact and age of the person. FATIGUE FRACTURES These occur after the bone has been under recurrent stress. A typical example is the march fracture of the second toe, from which army recruits suffer after long marches. PATHOLOGICAL FRACTURES These occur in bone which is already diseased – for example, by osteoporosis (see below) in post-menopausal women. Such fractures are typically crush fractures of the vertebrae, fractures of the neck of the femur, and COLLES’ FRACTURE (of the wrist). Pathological fractures also occur in bone which has secondary-tumour deposits. GREENSTICK FRACTURES These occur in young children whose bones are soft and bend, rather than break, in response to stress. The bone tends to buckle on the side opposite to the force. Greenstick fractures heal quickly but still need any deformity corrected and plaster of Paris to maintain the correction. COMPLICATED FRACTURES These involve damage to important soft tissue such as nerves, blood vessels or internal organs. In these cases the soft-tissue damage needs as much attention as the fracture site. COMMINUTED FRACTURES A fracture with more than two fragments. It usually means that the injury was more violent and that there is more risk of damage to vessels and nerves. These fractures are unstable and take longer to unite. Rehabilitation tends to be protracted. DEPRESSED FRACTURES Most commonly found in skull fractures. A fragment of bone is forced inwards so that it lies lower than the level of the bone surrounding it. It may damage the brain beneath it.

HAIR-LINE FRACTURES These occur when the bone is broken but the force has not been severe enough to cause visible displacement. These fractures may be easily missed. Symptoms and signs The fracture site is usually painful, swollen and deformed. There is asymmetry of contour between limbs. The limb is held uselessly. If the fracture is in the upper

limb, the arm is usually supported by the patient; if it is in the lower limb then the patient is not able to bear weight on it. The limb may appear short because of muscle spasm.

Examination may reveal crepitus – a bony grating – at the fracture site. The diagnosis is con?rmed by radiography.

Treatment Healing of fractures (union) begins with the bruise around the fracture being resorbed and new bone-producing cells and blood vessels migrating into the area. Within a couple of days they form a bridge of primitive bone across the fracture. This is called callus.

The callus is replaced by woven bone which gradually matures as the new bone remodels itself. Treatment of fractures is designed to ensure that this process occurs with minimal residual deformity to the bone involved.

Treatment is initially to relieve pain and may involve temporary splinting of the fracture site. Reducing the fracture means restoring the bones to their normal position; this is particularly important at the site of joints where any small displacement may limit movement considerably.

with plaster of Paris. If closed traction does not work, then open reduction of the fracture may

be needed. This may involve ?xing the fracture with internal-?xation methods, using metal plates, wires or screws to hold the fracture site in a rigid position with the two ends closely opposed. This allows early mobilisation after fractures and speeds return to normal use.

External ?xators are usually metal devices applied to the outside of the limb to support the fracture site. They are useful in compound fractures where internal ?xators are at risk of becoming infected.

Consolidation of a fracture means that repair is complete. The time taken for this depends on the age of the patient, the bone and the type of fracture. A wrist fracture may take six weeks, a femoral fracture three to six months in an adult.

Complications of fractures are fairly common. In non-union, the fracture does not unite

– usually because there has been too much mobility around the fracture site. Treatment may involve internal ?xation (see above). Malunion means that the bone has healed with a persistent deformity and the adjacent joint may then develop early osteoarthritis.

Myositis ossi?cans may occur at the elbow after a fracture. A big mass of calci?ed material develops around the fracture site which restricts elbow movements. Late surgical removal (after 6–12 months) is recommended.

Fractured neck of FEMUR typically affects elderly women after a trivial injury. The bone is usually osteoporotic. The leg appears short and is rotated outwards. Usually the patient is unable to put any weight on the affected leg and is in extreme pain. The fractures are classi?ed according to where they occur:

subcapital where the neck joins the head of the femur.

intertrochanteric through the trochanter.

subtrochanteric transversely through the upper end of the femur (rare). Most of these fractures of the neck of femur

need ?xing by metal plates or hip replacements, as immobility in this age group has a mortality of nearly 100 per cent. Fractures of the femur shaft are usually the result of severe trauma such as a road accident. Treatment may be conservative or operative.

In fractures of the SPINAL COLUMN, mere damage to the bone – as in the case of the so-called compression fracture, in which there is no damage to the spinal cord – is not necessarily serious. If, however, the spinal cord is damaged, as in the so-called fracture dislocation, the accident may be a very serious one, the usual result being paralysis of the parts of the body below the level of the injury. Therefore the higher up the spine is fractured, the more serious the consequences. The injured person should not be moved until skilled assistance is at hand; or, if he or she must be removed, this should be done on a rigid shutter or door, not on a canvas stretcher or rug, and there should be no lifting which necessitates bending of the back. In such an injury an operation designed to remove a displaced piece of bone and free the spinal cord from pressure is often necessary and successful in relieving the paralysis. DISLOCATIONS or SUBLUXATION of the spine are not uncommon in certain sports, particularly rugby. Anyone who has had such an injury in the cervical spine (i.e. in the neck) should be strongly advised not to return to any form of body-contact or vehicular sport.

Simple ?ssured fractures and depressed fractures of the skull often follow blows or falls on the head, and may not be serious, though there is always a risk of damage which is potentially serious to the brain at the same time.

Compound fractures may result in infection within the skull, and if the skull is extensively broken and depressed, surgery is usually required to check any intercranial bleeding or to relieve pressure on the brain.

The lower jaw is often fractured by a blow on the face. There is generally bleeding from the mouth, the gum being torn. Also there are pain and grating sensations on chewing, and unevenness in the line of the teeth. The treatment is simple, the line of teeth in the upper jaw forming a splint against which the lower jaw is bound, with the mouth closed.

Congenital diseases These are rare but may produce certain types of dwar?sm or a susceptibility to fractures (osteogenesis imperfecta).

Infection of bone (osteomyelitis) may occur after an open fracture, or in newborn babies with SEPTICAEMIA. Once established it is very di?cult to eradicate. The bacteria appear capable of lying dormant in the bone and are not easily destroyed with antibiotics so that prolonged treatment is required, as might be surgical drainage, exploration or removal of dead bone. The infection may become chronic or recur.

Osteomalacia (rickets) is the loss of mineralisation of the bone rather than simple loss of bone mass. It is caused by vitamin D de?ciency and is probably the most important bone disease in the developing world. In sunlight the skin can synthesise vitamin D (see APPENDIX 5: VITAMINS), but normally rickets is caused by a poor diet, or by a failure to absorb food normally (malabsorbtion). In rare cases vitamin D cannot be converted to its active state due to the congenital lack of the speci?c enzymes and the rickets will fail to respond to treatment with vitamin D. Malfunction of the parathyroid gland or of the kidneys can disturb the dynamic equilibrium of calcium and phosphate in the body and severely deplete the bone of its stores of both calcium and phosphate.

Osteoporosis A metabolic bone disease resulting from low bone mass (osteopenia) due to excessive bone resorption. Su?erers are prone to bone fractures from relatively minor trauma. With bone densitometry it is now possible to determine individuals’ risk of osteoporosis and monitor their response to treatment.

By the age of 90 one in two women and one in six men are likely to sustain an osteoporosis-related fracture. The incidence of fractures is increasing more than would be expected from the ageing of the population, which may re?ect changing patterns of exercise or diet.

Osteoporosis may be classi?ed as primary or secondary. Primary consists of type 1 osteoporosis, due to accelerated trabecular bone loss, probably as a result of OESTROGENS de?ciency. This typically leads to crush fractures of vertebral bodies and fractures of the distal forearm in women in their 60s and 70s. Type 2 osteoporosis, by contrast, results from the slower age-related cortical and travecular bone loss that occurs in both sexes. It typically leads to fractures of the proximal femur in elderly people.

Secondary osteoporosis accounts for about 20 per cent of cases in women and 40 per cent of cases in men. Subgroups include endocrine (thyrotoxicosis – see under THYROID GLAND, DISEASES OF, primary HYPERPARATHYROIDISM, CUSHING’S SYNDROME and HYPOGONADISM); gastrointestinal (malabsorption syndrome, e.g. COELIAC DISEASE, or liver disease, e.g. primary biliary CIRRHOSIS); rheumatological (RHEUMATOID ARTHRITIS or ANKYLOSING SPONDYLITIS); malignancy (multiple MYELOMA or metastatic CARCINOMA); and drugs (CORTICOSTEROIDS, HEPARIN). Additional risk factors for osteoporosis include smoking, high alcohol intake, physical inactivity, thin body-type and heredity.

Individuals at risk of osteopenia, or with an osteoporosis-related fracture, need investigation with spinal radiography and bone densitometry. A small fall in bone density results in a large increase in the risk of fracture, which has important implications for preventing and treating osteoporosis.

Treatment Antiresorptive drugs: hormone replacement therapy – also valuable in treating menopausal symptoms; treatment for at least ?ve years is necessary, and prolonged use may increase risk of breast cancer. Cyclical oral administration of disodium etidronate – one of the bisphosphonate group of drugs – with calcium carbonate is also used (poor absorption means the etidronate must be taken on an empty stomach). Calcitonin – currently available as a subcutaneous injection; a nasal preparation with better tolerance is being developed. Calcium (1,000 mg daily) seems useful in older patients, although probably ine?ective in perimenopausal women, and it is a safe preparation. Vitamin D and calcium – recent evidence suggests value for elderly patients. Anabolic steroids, though androgenic side-effects (masculinisation) make these unacceptable for most women.

With established osteoporosis, the aim of treatment is to relieve pain (with analgesics and physical measures, e.g. lumbar support) and reduce the risk of further fractures: improvement of bone mass, the prevention of falls, and general physiotherapy, encouraging a healthier lifestyle with more daily exercise.

Further information is available from the National Osteoporosis Society.

Paget’s disease (see also separate entry) is a common disease of bone in the elderly, caused by overactivity of the osteoclasts (cells concerned with removal of old bone, before new bone is laid down by osteoblasts). The bone affected thickens and bows and may become painful. Treatment with calcitonin and bisphosphonates may slow down the osteoclasts, and so hinder the course of the disease, but there is no cure.

If bone loses its blood supply (avascular necrosis) it eventually fractures or collapses. If the blood supply does not return, bone’s normal capacity for healing is severely impaired.

For the following diseases see separate articles: RICKETS; ACROMEGALY; OSTEOMALACIA; OSTEOGENESIS IMPERFECTA.

Tumours of bone These can be benign (non-cancerous) or malignant (cancerous). Primary bone tumours are rare, but secondaries from carcinoma of the breast, prostate and kidneys are relatively common. They may form cavities in a bone, weakening it until it breaks under normal load (a pathological fracture). The bone eroded away by the tumour may also cause problems by causing high levels of calcium in the plasma.

EWING’S TUMOUR is a malignant growth affecting long bones, particularly the tibia (calfbone). The presenting symptoms are a throbbing pain in the limb and a high temperature. Treatment is combined surgery, radiotherapy and chemotherapy.

MYELOMA is a generalised malignant disease of blood cells which produces tumours in bones which have red bone marrow, such as the skull and trunk bones. These tumours can cause pathological fractures.

OSTEOID OSTEOMA is a harmless small growth which can occur in any bone. Its pain is typically removed by aspirin.

OSTEOSARCOMA is a malignant tumour of bone with a peak incidence between the ages of ten and 20. It typically involves the knees, causing a warm tender swelling. Removal of the growth with bone conservation techniques can often replace amputation as the de?nitive treatment. Chemotherapy can improve long-term survival.... bone, disorders of

See CLAVICLE.... collar-bone

A procedure in which cells – for example, from the pancreas – are taken from an aborted FETUS and then transplanted into the malfunctioning organ (pancreas) of an individual with a disorder of that organ (in this case, diabetes). The cells from the fetus are intended to take over the function of the host’s diseased or damaged cells. Fetal brain cells have also been transplanted into brains of people suffering from PARKINSONISM. These treatments are at an experimental stage.... fetal transplant

The bone which forms the forehead and protects the frontal lobes of the brain. Before birth, the frontal bone consists of two halves, and this division may persist throughout life – a deep groove remaining down the centre of the forehead. Above each eye is a heavy ridge in the bone, most marked in men; behind this, in the substance of the bone, is a cavity on each side (the frontal sinus) which communicates with the nose. CATARRH in these cavities produces the frontal headache characteristic of a ‘cold in the head’, and sometimes infection develops known as SINUSITIS (see NOSE, DISORDERS OF).... frontal bone

See BONE MARROW.... marrow

Either one of a pair of bones that form the top and sides of the cranium of the SKULL.... parietal bone

The outside bone on the thumb side of the HAND in the row of carpal (wrist) bones nearest to the forearm. Fracture of the scaphoid is a common wrist injury that usually occurs when someone falls on to their outstretched hand. The fracture may not be diagnosed at ?rst (even an X-ray may not be abnormal). Pain in and permanent damage to the wrist can occur.... scaphoid bone

See osteopetrosis.... marble bone disease

Transplantation of tissues or organs of the body are de?ned as an allotransplant, if from another person; an autotransplant, if from the patient him or herself – for example, a skin graft (see GRAFT; SKIN-GRAFTING); and a xenotransplant, if from an animal.

The pioneering success was achieved with transplantation of the kidney in the 1970s; this has been most successful when the transplanted kidney has come from an identical twin. Less successful have been live transplants from other blood relatives, while least successful have been transplants from other live donors and cadaver donors. The results, however, are steadily improving. Thus the one-year functional survival of kidneys transplanted from unrelated dead donors has risen from around 50 per cent to over 80 per cent, and survival rates of 80 per cent after three years are not uncommon. For a well-matched transplant from a live related donor, the survival rate after ?ve years is around 90 per cent. And, of course, if a transplanted kidney fails to function, the patient can always be switched on to some form of DIALYSIS. In the United Kingdom the supply of cadaveric (dead) kidneys for transplantation is only about half that necessary to meet the demand.

Other organs that have been transplanted with increasing success are the heart, the lungs, the liver, bone marrow, and the cornea of the eye. Heart, lung, liver and pancreas transplantations are now carried out in specialist centres. It is estimated that in the United Kingdom, approximately 200 patients a year between the ages of 15 and 55 would bene?t from a liver transplant if an adequate number of donors were available. More than 100 liver transplants are carried out annually in the United Kingdom and one-year-survival rates of up to 80 per cent have been achieved.

The major outstanding problem is how to prevent the recipient’s body from rejecting and destroying the transplanted organ. Such rejection is part of the normal protective mechanism of the body (see IMMUNITY). Good progress has been made in techniques of tissue-typing and immunosuppression to overcome the problem. Drugs are now available that can suppress the immune reactions of the recipient, which are responsible for the rejection of the transplanted organ. Notable among these are CICLOSPORIN A, which revolutionised the success rate, and TACROLIMUS, a macrolide immunosuppressant.

Another promising development is antilymphocytic serum (ALS), which reduces the activity of the lymphocytes (see LYMPHOCYTE) cells which play an important part in maintaining the integrity of the body against foreign bodies.

Donor cards are now available in all general practitioners’ surgeries and pharmacies but, of the millions of cards distributed since 1972, too few have been used. The reasons are complex but include the reluctance of the public and doctors to consider organ donation; poor organisation for recovery of donor kidneys; and worries about the diagnosis of death. A code of practice for procedures relating to the removal of organs for transplantation was produced in 1978, and this code has been revised in the light of further views expressed by the Conference of Medical Royal Colleges and Faculties of the United Kingdom on the Diagnosis of Brain Death. Under the Human Tissue Act 1961, only the person lawfully in possession of the body or his or her designate can authorise the removal of organs from a body. This authorisation may be given orally.

Patients who may become suitable donors after death are those who have suffered severe and irreversible brain damage – since such patients will be dependent upon arti?cial ventilation. Patients with malignant disease or systemic infection, and patients with renal disease, including chronic hypertension, are unsuitable.

If a patient carries a signed donor card or has otherwise recorded his or her wishes, there is no legal requirement to establish lack of objection on the part of relatives – although it is good practice to take account of the views of close relatives. If a relative objects, despite the known request by the patient, sta? will need to judge, according to the circumstances of the case, whether it is wise to proceed with organ removal. If a patient who has died is not known to have requested that his or her organs be removed for transplantation after death, the designated person may only authorise the removal if, having made such reasonable enquiry as may be practical, he or she has no reason to believe (a) that the deceased had expressed an objection to his or her body being so dealt with after death, or (b) that the surviving spouse or any surviving relative of the deceased objects to the body being so dealt with. Sta? will need to decide who is best quali?ed to approach the relatives. This should be someone with appropriate experience who is aware how much the relative already knows about the patient’s condition. Relatives should not normally be approached before death has occurred, but sometimes a relative approaches the hospital sta? and suggests some time in advance that the patient’s organs might be used for transplantation after death. The sta? of hospitals and organ exchange organisations must respect the wishes of the donor, the recipient and their families with respect to anonymity.

Relatives who enquire should be told that some post-mortem treatment of the donor’s body will be necessary if the organs are to be removed in good condition. It is ethical (see ETHICS) to maintain arti?cial ventilation and heartbeat until removal of organs has been completed. This is essential in the case of heart and liver transplants, and many doctors think it is desirable when removing kidneys. O?cial criteria have been issued in Britain to recognise when BRAIN-STEM DEATH has occurred. This is an important protection for patients and relatives when someone with a terminal condition

– usually as a result of an accident – is considered as a possible organ donor.... transplantation

The insertion of a piece of bone from another site or from another person to ?ll a defect, provide supporting tissue, or encourage the growth of new bone.... bone transplant

An operation in which a patient’s diseased lungs and heart are removed and replaced with donor organs from someone who has been certi?ed as ‘brain dead’ (see BRAIN-STEM DEATH). As well as the technical diffculties of such an operation, rejection by the recipient’s tissues of donated heart and lungs has proved hard to overcome. Since the early 1990s, however, immunosuppressant drug therapy (see CICLOSPORIN; TRANSPLANTATION) has facilitated the regular use of this type of surgery. Even so, patients receiving transplanted hearts and lungs face substantial risks such as lung infection and airway obstruction as well as the long-term problems of transplant rejection.... heart-lung transplant

UK legislation that lays down the framework and rules governing organ transplantation. The UK Transplant Support Service Authority (UKTSSA), a special health authority set up in 1991, is responsible for administering the NHS Organ Donor Registry and the Act (see APPENDIX 7: STATUTORY ORGANISATIONS).... human organs transplants act

See TRANSPLANTATION.... organ transplantation

Also called osteitis deformans, this is a chronic disease in which the bones (see BONE) – especially those of the skull, limbs, and spine – gradually become thick and also soft, causing them to bend. It is said to be the most common form of bone disease in the world, and it is estimated that some 600,000 people in England may suffer from it. It seldom occurs under the age of 40. Pain is its most unpleasant manifestation. The cause is not known, and there is no known cure, but satisfactory results are being obtained from the use of CALCITONIN and a group of drugs known as BISPHOSPHONATES

(e.g. etidronate). Those with the disease can obtain help and advice from the National Association for the Relief of Paget’s Disease.... paget’s disease of bone

Before the advent of small-bowel transplants, long-term intravenous feeding (total parenteral nutrition or TPN) was the last option for patients with chronic intestinal failure. Most recipients are children, and small-bowel transplantation is currently reserved for patients unable to continue on long-term parenteral nutrition. The main constraints to small-bowel transplantation are the intensity of rejection (necessitating high levels of immunosuppression), and the lack of donors who are the same size as the recipient (a particular problem for children).... small-bowel transplantantion

In the UK, this NHS authority (UKTSSA) provides a 24-hour service for matching, allocating and distributing organs. It is also responsible for keeping the records of all patients awaiting transplants. Established in 1991, the authority allocates donor organs without favour, following protocols set by advisory groups. It also administers the Human Organ Transplant Act on behalf of the Department of Health. (See TRANSPLANTATION.)... transplant support services authority

May be myeloma (tumour-like over-growth of bone marrow tissue, a giant cell sarcoma, a medullary tumour or secondary deposit from breast, lung, prostate cancer etc. Risk of fracture. Inflammation of the bone – Yarrow. Comfrey. See: MYELOMA, SARCOMA. ... cancer – bone

A localized collection of pus in a bone (see osteomyelitis).... bone abscess

A procedure to obtain a sample of cells from the bone marrow (aspiration biopsy) or a small core of bone with marrow inside (trephine biopsy). The sample is usually taken, under local anaesthesia, from the sternum (breastbone) or iliac crests (upper part of the hip-bones). Microscopic examination gives information on the development of the blood components

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

A cosmetic operation in which hairy sections of scalp are removed and transplanted to hairless areas to treat alopecia (baldness). There are several different techniques.

In strip grafting, a strip of skin and hair is taken from a donor site, usually at the back of the scalp or behind the ears. The removed hairs and their follicles are then inserted into numerous incisions made in a bald area, known as the recipient site. The procedure usually takes 60–90 minutes. The patient is given a mild sedative and anaesthetic on the donor and recipient sites. The donor site heals in about 5 days. Transplanted hairs fall out shortly afterwards, but new hairs grow from the follicles 3 weeks to 3 months later.

Other transplant techniques include punch grafting, in which a punch is used to remove small areas of bald scalp, which are replaced with areas of hairy scalp; flap grafting, in which flaps of hairy skin are lifted, rotated, and stitched to replace bald areas; and male pattern baldness reduction, which involves cutting out areas of bald skin and stretching surrounding areas of hair-bearing scalp to replace them.... hair transplant

Replacement of a patient’s damaged or diseased heart with a healthy heart taken from a donor at the time of death. Typically, transplant patients have advanced coronary artery disease or cardiomyopathy. During the operation, the function of the heart is taken over by a heart–lung machine.

Most of the diseased heart is removed, but the back walls of the atria (upper chambers) are left in place.

The ventricles (upper chambers) are then attached to the remaining areas of the recipient’s heart.

Once the immediate post-operative period is over, the outlook is good.

Patients face the long-term problems associated with other forms of transplant surgery.

(See also heart–lung transplant.)... heart transplant

Replacement of a diseased liver with a healthy liver removed from a donor. Liver transplants are most successful in the treatment of advanced liver cirrhosis in people with chronic active hepatitis or primary biliary cirrhosis. People who have primary liver cancer are rarely considered for transplantation because there is a high risk that the tumour will recur.During this procedure, the liver, gallbladder, and portions of the connected blood and bile vessels are removed.

The donor organs and vessels are connected to the recipient’s vessels.

After the transplant, the recipient is monitored in an intensive care unit for a few days and remains in hospital for up to 4 weeks.... liver transplant

One of 5 long, cylindrical bones within the hand. The bones run from the wrist to the base of each digit, with the heads of the bones forming the knuckles.... metacarpal bone

One of 5 long, cylindrical bones within the foot. The bones make up the central skeleton of the foot and are held in an arch by the surrounding ligaments.... metatarsal bone

The front part of the fused bones that form the pelvis.... pubic bone

Another term for kidney transplant.... renal transplant

Replacement of a diseased organ or tissue with a healthy, living substitute. The organ is usually taken from a person who has just died. Some kidneys are transplanted from a patient’s living relatives (see organ donation). The results of surgery have also been improved by testing for histocompatibility antigens and tissue-typing.

Rejection is a major problem. However, a combination of a corticosteroid drug and ciclosporin are given in order to suppress this response.

Every patient who undergoes an organ transplant operation must take immunosuppressant drugs indefinitely. (See also heart transplant; heart–lung transplant; liver transplant; kidney transplant.)... transplant surgery

(BAHA) a specialized form of *hearing aid for patients with certain forms of conductive *deafness. A small titanium screw is surgically fixed into the bone of the skull behind the external ear using a process called *osseointegration. Sound energy is passed from a miniature microphone and amplifier to the screw, through the bone, to the *cochlea.... bone-anchored hearing aid

a group of *growth factors that promote new bone formation. Bone morphogenic protein (BMP), a naturally occurring substance that induces *osteoblast formation, has been genetically synthesized to form bone morphogenetic protein, which stimulates new bone formation and assists with fracture healing. Other bone growth factors include a type of transforming growth factor (TGF?) and insulin-like growth factor II (IGF-II), which encourage collagen formation.... bone growth factors

the largest bone of the wrist (see carpus). It articulates with the scaphoid and lunate bones behind, with the second, third, and fourth metacarpal bones in front, and with the trapezoid and hamate laterally.... capitate bone

the outer bone of the *tarsus, which articulates with the fourth and fifth metatarsal bones in front and with the calcaneus (heel bone) behind.... cuboid bone

an imaging investigation of a patient’s bone using radioactive *tracers. *Technetium-99m phosphate is injected intravenously and absorbed into the hydroxyapatite crystals of bone. It concentrates in areas of increased blood flow and metabolism, such as areas of infection, trauma, and *neoplasia, and gives off radiation that can be detected by a *gamma camera, thereby producing a map or scan of activity in the target area. A bone scan is particularly useful in the diagnosis of subtle fractures (including stress fractures), avascular necrosis (see osteonecrosis), osteomyelitis, tumour spread (metastasis), and loosening of orthopaedic implants.... bone scan

a bone in the floor of the cranium that contributes to the nasal cavity and orbits. The part of the ethmoid forming the roof of the nasal cavity – the cribriform plate – is pierced with many small holes through which the olfactory nerves pass. See also nasal concha; skull.... ethmoid bone

(unciform bone) a hook-shaped bone of the wrist (see carpus). It articulates with the capitate and triquetral bones at the sides, with the lunate bone behind, and with the fourth and fifth metacarpal bones in front.... hamate bone

see orthotopic transplantation.... heterotopic transplantation

(innominate bone) a bone formed by the fusion of the ilium, ischium, and pubis. It articulates with the femur by the acetabulum of the ilium, a deep socket into which the head of the femur fits (see hip joint). Between the pubis and ischium, below and slightly in front of the acetabulum, is a large opening – the obturator foramen. The right and left hip bones form part of the *pelvis.... hip bone

a small isolated U-shaped bone in the neck, below and supporting the tongue. It is held in position by muscles and ligaments between it and the styloid process of the temporal bone.... hyoid bone

see hip bone.... innominate bone

(inca bone, incarial bone) the bone lying between the *parietal bones, at the back of the skull.... interparietal bone

a new technique still under evaluation for curing type 1 *diabetes mellitus, which involves the injection of donated cells from the pancreatic *islets of Langerhans into the liver, where it is hoped they will seed and survive. The transplanted cells then take over insulin production from the recipient’s diseased pancreas.... islet cell transplantation

the smallest bone of the face: either of a pair of rectangular bones that contribute to the orbits. See skull.... lacrimal bone

mature *bone, in which the collagen fibres are arranged parallel to each other to form multiple layers (*lamellae) with the osteocytes lying between the lamellae. It exists in two structurally different forms: cortical (compact) and cancellous (spongy) bone. See also woven bone.... lamellar bone

a bone of the wrist (see carpus). It articulates with the capitate and hamate bones in front, with the radius behind, and with the triquetral and scaphoid at the sides.... lunate bone

see zygomatic bone.... malar bone

a bone that develops in connective tissue by direct *ossification, without cartilage being formed first. The bones of the face and skull are membrane bones.... membrane bone

either of a pair of narrow oblong bones that together form the bridge and root of the nose. See skull.... nasal bone

a boat-shaped bone of the ankle (see tarsus) that articulates with the three cuneiform bones in front and with the talus behind.... navicular bone

(NHSBT) a *special health authority established in 2005 to provide a safe and reliable supply of blood, organs, stem cell services, and diagnostics to hospitals. NHSBT also provides specialist therapeutic apheresis services, which remove or replace a single component of blood (e.g. malignant white cells or low-density lipoprotein), at six sites in England.

NHS Blood and Transplant website... nhs blood and transplant

a saucer-shaped bone of the *skull that forms the back and part of the base of the cranium. At the base of the occipital are two occipital condyles: rounded surfaces that articulate with the first (atlas) vertebra of the backbone. Between the condyles is the foramen magnum, the cavity through which the spinal cord passes.... occipital bone

transplantation of a donor organ or tissue (usually the liver) into a recipient at the site where the recipient’s organ has been removed. In contrast, heterotopic transplantation involves the preservation of the recipient’s organ in its natural site and the addition of the donor organ at another site.... orthotopic transplantation

These have almost completely replaced BONE MARROW TRANSPLANT, used to treat malignancies such as LEUKAEMIA and LYMPHOMA for the past 20 years. The high doses of CHEMOTHERAPY or RADIOTHERAPY used to treat these diseases destroy the bone marrow which contains stem cells from which all the blood cells derive. In 1989 stem cells were found in the blood during recovery from chemotherapy. By giving growth factors (cytokines), the number of stem cells in the blood increased for about three to four days. In a peripheral-blood stem-cell transplant, these cells can be separated from the peripheral blood, without a general anaesthetic. The cells taken by either method are then frozen and returned intravenously after the chemotherapy or radiotherapy is completed. Once transplanted, the stem cells usually take less than three weeks to repopulate the blood, compared to a month or more for a bone marrow transplant. This means that there is less risk of infection or bleeding during the recovery from the transplant. The whole procedure has a mortality risk of less than 5 per cent – half the risk of a bone marrow transplant.... peripheral-blood stem-cell transplants

May be present at birth or due to infection (osteomyelitis, tuberculosis, etc), fractures from injury or accident, osteoporosis, Paget’s disease (deformity due to mineral deficiency), tumour or sarcoma, osteomalacia, rickets due to Vitamin D deficiency. Brittle-bone disease. Arthritis. See separate entries.

Comfrey decoction. 1 heaped teaspoon to cup water gently simmered 5 minutes; strain when cold; 1 cup – to which is added 20 drops Tincture Calendula (Marigold), thrice daily. Fenugreek seeds may be used as an alternative to Comfrey.

Alternative:– Mixture: equal parts liquid extracts: Comfrey, Marigold, St John’s Wort. One teaspoon in water or honey thrice daily.

Tablets/capsules. Fenugreek, St John’s Wort.

Topical. Comfrey, Fenugreek or Horsetail poultice.

Supplements. Vitamin A, C, E. Dolomite, Zinc.

Supportive. Exposure of site to sunlight.

Comfrey. The potential benefit of Comfrey root outweighs possible risk for bone disorders. ... bone disorders

Malignant growth in bone, which may originate in the bone itself (primary bone cancer) or, more commonly, occur as a result of cancer spreading from elsewhere in the body (secondary, or metatastic, bone cancer). Primary bone cancers are rare. The type that occurs most often is osteosarcoma. Other types include chondrosarcoma and fibrosarcoma. Bone cancer can also start in the bone marrow (see multiple myeloma and leukaemia). The treatment of primary bone cancer depends on the extent to which the disease has spread. If it remains confined to bone, amputation may be recommended; but it may be possible to remove the cancer and fill the defect with a bone graft. Radiotherapy or chemotherapy, or both, may also be needed

The cancers that spread readily to form secondary bone cancer are those of the breast, lung, prostate, thyroid, and kidney.

These bone metastases occur commonly in the spine, pelvis, ribs, and skull.

Pain is usually the main symptom.

Affected bones are abnormally fragile and may easily fracture.

Bone cancer that affects the spine may cause collapse or crushing of vertebrae, damaging the spinal cord and causing weakness or paralysis of one or more limbs.

Secondary bone cancers from the breast and prostate often respond to treatment with hormone antagonists.... bone cancer

Techniques for providing pictures that show the structure or function of bones. X-ray images are the most commonly used technique for diagnosing fractures and injuries. More detailed information is provided by tomography, CT scanning, or MRI, which can show tumours

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

A bone swelling that may be cancerous (see bone cancer) or noncancerous.

The most common type of noncancerous bone tumour is an osteochondroma.

Other types are osteoma and chondroma (see chondromatosis).

Treatment is only necessary if the tumour becomes very large or causes symptoms by pressing on other structures.

In such cases, the tumour can be removed by surgery.

Osteoclastoma (also called a giant cell tumour), which usually occurs in the arm or leg of a young adult, is tender and painful and has to be removed.... bone tumour

See corneal graft.... corneal transplant

A popular term for the small area at the back of the elbow where the ulnar nerve passes over a prominence of the humerus (upper-arm bone). A blow to the nerve causes acute pain, numbness, and a tingling sensation in the forearm and hand.... funny-bone

See bone marrow.... marrow, bone

The lower part of the temporal bone in the skull. It has a projection, known as the mastoid process, which can be felt behind the ear. The mastoid bone is honeycombed with air cells. These are connected to a cavity called the mastoid antrum, which leads into the middle ear. Infections of the middle ear (see otitis media) occasionally spread through the mastoid bone to cause acute mastoiditis.... mastoid bone

A measure of skeletal maturity used to assess physical development in children. X-rays, which show how

much bones have grown in a particular body area, are used to determine bone age. (See also age.)... bone age

An abnormal cavity in a bone.

Bone cysts typically develop at one end of a long bone and maybe discovered only by chance after a bone fracture at the site of the cyst.

Minor surgery to scrape out the cyst and fill the the cavity with bone chips usually cures the condition, although many small cysts do not need treatment.... bone cyst

The compactness of bone tissue in relation to its volume. A decrease in bone density is a normal part of aging. However, in some people, excessive loss of density (see osteoporosis) can lead to fractures. Less commonly, an increase in bone density (see osteosclerosis) occurs in certain disorders (see osteopetrosis; Paget’s disease). Bone density can be measured by a technique known as densitometry, which uses low-dose X-rays.... bone density

either of a pair of approximately L-shaped bones of the face that contribute to the hard *palate, the nasal cavity, and the orbits. See skull.... palatine bone

see temporal bone.... petrous bone

the smallest bone of the wrist (*carpus): a pea-shaped bone that articulates with the triquetral bone and, indirectly by cartilage, with the ulna.... pisiform bone

see transplantation.... renal transplantation

a bone that is formed by replacing cartilage with bony material.... replacement bone

an oval nodule of bone that lies within a tendon and slides over another bony surface. The patella (kneecap) and certain bones in the hand and foot are sesamoid bones.... sesamoid bone

a bone forming the base of the cranium behind the eyes. It consists of a body, containing air spaces continuous with the nasal cavity (see paranasal sinuses); two wings that form part of the orbits; and two pterygoid processes projecting down from the point where the two wings join the body. See skull.... sphenoid bone

see temporal bone.... squamous bone

either of a pair of bones of the cranium. The squamous portion forms part of the side of the cranium. The petrous part contributes to the base of the skull and contains the middle and inner ears. Below it are the *mastoid process, *styloid process, and zygomatic process (see zygomatic arch). See also skull.... temporal bone

a bone of the wrist (see carpus). It articulates with the second metatarsal bone in front, with the scaphoid bone behind, and with the trapezium and capitate bones on either side.... trapezoid bone

see nasal concha.... turbinate bone

see hamate bone.... unciform bone

one of a number of small bones that occur in the cranial sutures.... wormian bone

immature bone, in which the collagen fibres are arranged haphazardly and the cells have no specific orientation. It is typically found in the early stages of fracture healing, eventually being replaced by mature *lamellar bone.... woven bone

(zygoma, malar bone) either of a pair of bones that form the prominent part of the cheeks and contribute to the orbits. See skull.... zygomatic bone