The British Medical Association ILLUSTRATED MEDICAL DICTIONARY CORONARY ARTERY coronary Any structure that encircles like a crown. The term usually refers to the vSeunpae rciaovr a Aorta cLoerfot nmaaryin caolsroo nsaorym aerttiemrieess eunsceidrc lainsg ath en ohnemaret.d Iitc aisl artery term for a heart attack (see myocardial Pulmonary Left infarction). veins circumflex coronary artery Either of the 2 main artery arteries that supply the tissues of the heart with oxygen-rich blood. These arteries, known as the left and right main Left coronary arteries, arise directly from the Right anterior aorta. The term coronary artery is also m c aoratreionrnyary daretescryending aopffp flrioemd ttoh ea nmy aoifn t hcoer aorntaeryie asr theraite sb,r asnuch Coronary as the left circumflex artery and the left vein anterior descending artery. Blockage of a Inferior Descending coronary artery as a result of athero- vena cava aorta sclerosis can lead to myocardial infarction. (See also coronary artery disease.) Essential A–Z quick reference to over 5,500 medical terms The British Medical Association ILLUSTRATED MEDICAL DICTIONARY A Dorling Kindersley Book ABDOMEN ABDOMINAL SWELLING A intake, eating unwisely, or an attack of diarrhoea. Pain in the lower abdomen is common during menstruation but is occasionally due to a gynaecological disorder such as endometriosis. Cystitis is a common cause of pain or discom- fort in the abdomen. Bladder distension A asls oa craeussuelt a obfd oumrininaaryl poabins.t ruction may abdomen The region of the body be- Abdominal colic is pain that occurs tween the chest and the pelvis. The every few minutes as one of the internal abdominal cavity is bounded by the ribs organs goes into muscular spasm in an and diaphragm above, and by the pelvis attempt to overcome an obstruction below, with the spine and abdominal such as a stone or an area of inflamma- muscles forming the back, side, and tion. The attacks of colic may become front walls. It contains the liver, stom- more severe and may be associated ach, intestines, spleen, pancreas, and with vomiting (see abdomen, acute). kidneys. In the lower abdomen, enclosed Peptic ulcer often produces recurrent by the pelvis, are the bladder, rectum, gnawing pain. Other possible causes of and, in women, the uterus and ovaries. abdominal pain are infection, such as pyelonephritis, and ischaemia (lack of ABDOMEN blood supply), as occurs when a volvu- lus (twisting of the intestine) obstructs Stomach blood vessels. Tumours affecting an Liver abdominal organ can cause pain. Abdo- minal pain can also result from anxiety. For mild pain, a wrapped hot-water Large bottle is often effective. Pain due to intestine A abredao omfen pbye ptfioco udl ceorr cabny btea ktienmg poarnatraiclyid r edlireuvgesd. Small Abdominal pain that is not relieved by intestine vomiting, persists for more than 6 hours, Rectum oinrg i sr eaqsusoirceisa tuedrg ewnith m sewdeiactailn ga toter nfatiionnt-. Urgent attention is also necessary if pain is accompanied by persistent vom- abdomen, acute Persistent, severe ab- iting, vomiting of blood, or passing of dominal pain of sudden onset, usually bloodstained or black faeces. Unex- associated with spasm of the abdomi- plained weight loss or changes in bowel nal muscles, vomiting, and fever. habits should always be investigated. The most common cause of an acute Investigation of abdominal pain may abdomen is peritonitis. Other causes include the use of imaging tests such as include appendicitis, abdominal injury, ultrasound scanning, and endoscopic perforation of an internal organ due to examination in the form of gastroscopy, disorders such as peptic ulcer or diver- colonoscopy, or laparoscopy. ticular disease. Acute abdominal pain abdominal swelling Enlargement of commonly begins as a vague pain in the the abdomen. Abdominal swelling is a centre but then becomes localized. natural result of obesity and growth of An acute abdomen requires urgent the uterus during pregnancy. Wind in the medical investigation that may involve stomach or intestine may cause uncom- a laparoscopy or a laparotomy. Treat- fortable, bloating distension of the ment depends on the underlying cause. abdomen. Some women experience ab- abdominal pain Discomfort in the ab- dominal distension due to temporary domen. Mild abdominal pain is common water retention just before menstrua- and is often due to excessive alcohol tion. Other causes may be more serious. 4 ABDOMINAL THRUST ABSCESS For instance, ascites (accumulation of ABO blood groups See blood groups. A fluid between organs) may be a symp- abortifacient An agent that causes abor- tom of cancer or disease of the heart, tion. In medical practice, abortion is kidneys, or liver; swelling may also be induced using prostaglandin drugs, due to intestinal obstruction (see intes- often given as vaginal pessaries. tine, obstruction of) or an ovarian cyst. abortion In medical terminology, either Diagnosis of the underlying cause may spontaneous abortion (see miscarriage) involve abdominal X-rays, ultrasound or medically induced termination of scanning, laparotomy, or laparoscopy. In pregnancy (see abortion, induced). ascites, some fluid between organs may abortion, induced Medically induced be drained for examination. termination of pregnancy. Abortion may abdominal thrust A first-aid treatment be performed if continuation of the for choking, in which sharp upward pres- pregnancy would risk the woman’s life, sure is applied to the upper abdomen if the mental or physical health of the to dislodge a foreign body obstructing woman or her existing children is at the airway. The technique is also known risk, or if there is a substantial risk of as the Heimlich manoeuvre. handicap to the baby. abdominal X-ray An X-ray examina- Depending on the stage of pregnancy, tion of the abdominal contents. X-rays termination may be induced by using can show whether any organ is enlarged drugs or by the surgical technique of and can detect swallowed foreign bod- vacuum suction curettage, under either ies in the digestive tract. They also show a general or local anaesthetic, during patterns of fluid and gas: distended which the fetal and placental tissues are loops of bowel containing fluid often removed. Complications are rare. indicate an obstruction (see intestine, abrasion Also called a graze, a wound obstruction of); gas outside the intestine on the skin surface that is caused by indicates intestinal perforation. scraping or rubbing. Calcium, which is opaque to X-rays, is abrasion, dental The wearing away of present in most kidney stones (see tooth enamel, often accompanied by the calculus, urinary tract) and in some erosion of dentine (the layer beneath gallstones and aortic aneurysms; these the enamel) and cementum (the bone- can sometimes be detected on an like tissue that covers the tooth root), abdominal X-ray. usually through too-vigorous brushing. abducent nerve The 6th cranial nerve. Abraded areas are often sensitive to It supplies the lateral rectus muscle of cold or hot food or drink, and a desensi- each eye, which is responsible for mov- tizing toothpaste and/or protection with ing the eyeball outwards. The nerve a bonding (see bonding, dental) agent or originates in the pons (part of the brain- filling may be needed. stem) and passes along the base of the abreaction In psychoanalysis, the pro- brain, entering the back of the eye socket cess of becoming consciously aware of through a gap between the skull bones. repressed (buried) thoughts and feelings. abduction Movement of a limb away In Freudian theory, abreaction ideally from the central line of the body, or of a occurs by way of catharsis. digit away from the axis of a limb. Mus- abscess A collection of pus formed as a cles that carry out this movement are result of infection by microorganisms, called abductors. (See also adduction.) usually bacteria. Abscesses may develop ablation Removal or destruction of dis- in any organ and in the soft tissues eased tissue by excision (cutting away), beneath the skin in any area. Common cryosurgery (freezing), radiotherapy, dia- sites include the armpit, breast (see thermy (burning), or laser treatment. breast abscess), groin, and gums (see abnormality A physical deformity or abscess, dental). Rarer sites include the malformation, a behavioural or mental liver (see liver abscess) and the brain problem, or a variation from normal in (see brain abscess). the structure or function of a cell, tis- Common bacteria, such as staphylo- sue, or organ in the body. cocci, are the usual cause of abscesses, 5 ABSCESS, DENTAL ACANTHOSIS NIGRICANS A a thltehmo,u gahn df uanmgaole bianefecatrieo nasn ciamnp ocratuasnet ABSCESS, DENTAL cause of liver abscesses (see amoebia- Enamel Decay sis). Infectious organisms usually reach tinhteeyr npael noertgratnes tvisas uthees bulnodoedrs ttrheaem s,k oinr Dentine Gum through a wound. An abscess may cause pain, depending Pulp on where it occurs. Most larger absces- Blood ses cause fever, sweating, and malaise. vessel Those that are close to the skin often Nerve cause obvious redness and swelling. Antibiotics, antifungal drugs, or amoe- Jawbone bicides are usually prescribed as Abscess appropriate. Most abscesses also need to be drained (see drain, surgical), and in some cases a tube may be left in place to allow continuous drainage. Some abscesses burst and drain spon- An abscess in a periodontal pocket can taneously. Occasionally, an abscess usually be treated by the dentist scrap- within a vital organ damages enough ing away infected material. surrounding tissue to cause permanent absence In medical terms, a temporary loss of normal function, or even death. loss or impairment of consciousness abscess, dental A pus-filled sac in the that occurs in some forms of epilepsy, tissue around the root of a tooth. An typically generalized absence (petit abscess may occur when bacteria mal) seizures in childhood. invade the pulp (the tissues in the cen- absorption The process by which flu- tral cavity of a tooth) as a result of ids or other substances are taken up by dental caries, which destroys the tooth’s body tissues. The term is commonly enamel and dentine, allowing bacteria applied to the uptake of the nutrients to reach the pulp. Bacteria can also gain from food into blood and lymph from access to the pulp when a tooth is the digestive tract. The major site of injured. The infection in the pulp then absorption is the small intestine, which spreads into the surrounding tissue to is lined with microscopic finger-like form an abscess. Abscesses can also projections called villi (see villus). The result from periodontal disease, in which villi greatly increase the surface area of bacteria accumulate in pockets that the intestine, thereby increasing the form between the teeth and gums. rate of absorption. The affected tooth aches or throbs, acanthosis nigricans A rare condition and biting or chewing is usually in which thickened dark patches of skin extremely painful. The gum around the appear in the groin, armpits, neck, and tooth is tender and may be red and other skin folds. The condition may swollen. An untreated abscess eventu- occur in young people as a genetic dis- ally erodes a sinus (channel) through order or as the result of an endocrine the jawbone to the gum surface, where disorder such as Cushing’s syndrome. It it forms a swelling known as a gumboil. also occurs in people with carcinomas As the abscess spreads, the glands in of the lung and other organs. the neck and the side of the face may Pseudoacanthosis nigricans is a much become swollen, and fever may develop. more common condition, usually seen Treatment may consist of draining the in dark-complexioned people who are abscess, followed by root-canal treat- overweight. In this form, the skin in fold ment of the affected tooth, but in some areas is both thicker and darker than the cases extraction of the tooth is neces- surrounding skin, and there is usually sary. Antibiotics are prescribed if the excessive sweating in affected areas. The infection has spread beyond the tooth. condition may improve with weight loss. 6 ACARBOSE ACETYLCHOLINESTERASE INHIBITORS acarbose A drug that is used to treat more difficult and results in a form of A type 2 diabetes mellitus. Acarbose acts longsightedness called presbyopia. on enzymes in the intestines, inhibiting acebutolol A beta-blocker drug used to the digestion of starch and therefore treat hypertension, angina pectoris, and slowing the rise in blood glucose levels certain types of arrhythmia in which the after a carbohydrate meal. heart beats too rapidly. accessory nerve The 11th cranial nerve. ACE inhibitor drugs A group of vaso- Unlike the other cranial nerves, most of dilator drugs used to treat heart failure, the accessory nerve originates from the hypertension, and diabetic nephropathy. spinal cord. The small part of the nerve ACE (angiotensin converting enzyme) in- that originates from the brain supplies hibitors are often prescribed with other many muscles of the palate, pharynx drugs such as diuretic drugs or beta- (throat), and larynx (voice box). Damage blocker drugs. Possible side effects to this part of the nerve may cause diffi- include nausea, loss of taste, headache, culty in speaking and swallowing. The dizziness, and dry cough. spinal part of the nerve supplies large acetaminophen An analgesic drug muscles of the neck and back, notably more commonly known as paracetamol. the sternomastoid and trapezius. Dam- acetazolamide A drug that is used in age to the spinal fibres of the nerve the treatment of glaucoma and, occa- paralyses these muscles. sionally, to prevent or treat symptoms accidental death Death that occurs as of mountain sickness. Possible adverse a direct result of an accident. A high pro- effects include lethargy, nausea, diar- portion of deaths in young adults, rhoea, and impotence. particularly among males, are acciden- acetic acid The colourless, pungent, org- tal. Many of these deaths are due to anic acid that gives vinegar its sour road traffic accidents, drowning, or drug taste. In medicine, acetic acid is an overdose. Falls in the home and burning ingredient of antiseptic gels that are or asphyxiation due to fire are common used for certain vaginal infections. causes of accidental death in elderly acetylcholine A type of neurotransmit- people. Fatal accidents at work have ter (a chemical that transmits messages become less common with the intro- between nerve cells or between nerve duction of effective safety measures. and muscle cells). Acetylcholine is the accommodation Adjustment, especially neurotransmitter found at all nerve- the process by which the eye adjusts muscle junctions and at many other itself to focus on near objects. At rest, sites in the nervous system. The actions the eye is focused for distant vision, of acetylcholine are called cholinergic when its lens is thin and flat. To make actions, and these can be blocked by focusing on a nearer object possible, anticholinergic drugs. the ciliary muscle of the eye contracts, acetylcholinesterase inhibitors A which reduces the pull on the outer rim group of drugs that are used in the of the lens, allowing it to become thicker treatment of mild to moderate dementia and more convex. due to Alzheimer’s disease, in which With age, the lens loses its elasticity. there is a deficiency of the neuro- This makes accommodation more and transmitter acetylcholine in the brain. ACCOMMODATION Light rays from Point of Light rays from Point of near object focus distant object focus Rounded Ciliary lens bends Ciliary Flattened muscle the light muscle lens NEAR FOCUS DISTANT FOCUS 7 ACETYLCYSTEINE ACID–BASE BALANCE A Drugs such as donepezil and rivastig- Violent stretching of the tendon can mine work by blocking the action of cause it to rupture; in such cases, surgi- acetylcholinesterase, the enzyme in the cal repair may be necessary. brain responsible for the breakdown of achlorhydria Absence of stomach acid acetylcholine. This raises acetylcholine secretions. This may be due to chronic levels, and, in half of all patients, the atrophic gastritis or to an absence or drugs slow the rate of progression of malfunction of acid-producing parietal dementia. They have no effect on cells in the stomach lining. Achlorhydria dementia due to other causes, such as may not produce symptoms but is asso- stroke or head injury, however. Com- ciated with stomach cancer, however, mon side effects include nausea, and is a feature of pernicious anaemia dizziness, and headache. Rarely, diffi- (see anaemia, megaloblastic). culty in passing urine may occur. achondroplasia A rare genetic disor- acetylcysteine A drug used in the treat- der of bone growth that leads to short ment of paracetamol overdose and as a stature. The condition is caused by a mucolytic drug to loosen sputum. When dominant gene (see genetic disorders) the drug is taken in large doses, vomiting but often arises as a new mutation. The or rash may occur as rare side effects. long bones of the arms and legs are achalasia A rare condition of unknown affected mainly. The cartilage that links cause in which the muscles at the lower each bone to its epiphysis (the growing end of the oesophagus and the sphinc- area at its tip) is converted to bone too ter (valve) between the oesophagus and early, preventing further limb growth. the stomach fail to relax to let food into Those affected have short limbs, a well- the stomach after swallowing. As a developed trunk, and a head of normal result, the lowest part of the oesopha- size except for a protruding forehead. gus is narrowed and becomes blocked aciclovir An antiviral drug that can be with food, while the part above widens. taken by mouth, used topically, or given Symptoms include difficulty and pain intravenously to reduce the severity of with swallowing and pain in the lower viral infections including herpes simplex chest and upper abdomen. and herpes zoster. Local adverse reac- A barium swallow (a type of barium tions commonly occur after topical use. X-ray examination) and gastroscopy may Other side effects are uncommon but be performed to investigate achalasia. can include nausea and vomiting. Oesophageal dila- acid A substance defined as a donor of ACHILLES TENDON tation allows the hydrogen ions (hydrogen atoms with mCaulsf cle oweidsoenpehda gufosr tolo bneg puolessi,t ivweh elne cmtrixceadl cwhaitrhg eosr) . dAicsisdo lmveodle icn- periods. Surgery to water, split up to release their con- cut some of the stituent ions; all acids release hydrogen muscles at the sto- as the positive ion. (See also acid–base mach entrance may balance; alkali.) be necessary. acid–base balance A combination of Achilles Achilles tendon mechanisms that ensures that the body’s tendon The tendon that fluids are neither too acid nor too alka- raises the heel. line (alkalis are also called bases). The Achilles ten- The body has three mechanisms for don is formed from maintaining normal acid–base balance: the calf muscles buffers, breathing, and the activities of Heel (gastrocnemius, the kidneys. Buffers are substances in soleus, and plan- the blood that neutralize acid or alka- tar muscles) and line wastes. Rapid breathing results in is attached to the the blood becoming less acidic; slow calcaneus (heel-bone). Minor injuries to breathing has the opposite effect. The the Achilles tendon are common and kidneys regulate the amounts of acid or can result in inflammation (tendinitis). alkaline wastes in the urine. 8 ACIDOSIS ACOUSTIC NEUROMA Disturbances of the body’s acid–base Acne develops in areas of skin with a A balance result in either acidosis (exces- high concentration of sebaceous glands, sive blood acidity) or alkalosis (excessive mainly the face, centre of the chest, blood alkalinity). upper back, shoulders, and around the acidosis A disturbance of the body’s neck. Milia (whiteheads), comedones acid–base balance in which there is an (blackheads), nod- accumulation of acid or loss of alkali ules (firm swel- ACNE (base). There are 2 types of acidosis: lings beneath the Sebaceous Inflamed skin m Oetnaeb ofloicrm an do fr esmpeirtatboorlyi.c acidosis is (slkairng)e, r, aflnudid -fciyllsetds gland Plug Pus ketoacidosis, which occurs in uncon- swellings) are the Hair trolled diabetes mellitus and starvation. most commonly Metabolic acidosis may also be caused occurring spots. by loss of bicarbonate (an alkali) as a Some, particularly result of severe diarrhoea. In kidney fail- cysts, leave scars ure, there is insufficient excretion of after they heal. acid in the urine. There is no inst- Respiratory acidosis occurs if breathing ant cure for acne, fails to remove enough carbon dioxide but washing the from the lungs. The excess carbon di- affected areas at oxide remains in the bloodstream, least twice daily where it dissolves to form carbonic acid. may help to keep Impaired breathing leading to respira- it under control. ACNE SPOT tory acidosis may be due to chronic Topical drug treat- obstructive pulmonary disease (see pul- ments, such as benzoyl peroxide or monary disease, chronic obstructive), retinoic acid, unblock the pores and bronchial asthma, or airway obstruction. promote healing. Ultraviolet light can acid reflux Regurgitation of acidic fluid be beneficial. If topical treatment has from the stomach into the oesophagus failed, oral drug treatment with anti- due to inefficiency of the muscular valve biotics, hormones, or isotretinoin may be at the lower end of the oesophagus. given. Acne improves slowly over time, Also known as gastro-oesophageal often clearing up by the end of the reflux disease (GORD), acid reflux may teenage years. inflame the oesophagus, resulting in acoustic nerve The part of the vestibu- heartburn due to oesophagitis. It may locochlear nerve (the 8th cranial nerve) occur in pregnancy and often affects that is concerned with hearing. It is also overweight people. known as the auditory nerve. acne A chronic skin disorder caused by acoustic neuroma A rare, noncancer- inflammation of the hair follicles and ous tumour arising from supporting sebaceous glands in the skin. The most cells that surround the 8th cranial nerve common type is acne vulgaris, which (see acoustic nerve), usually within the almost always develops during puberty. internal auditory meatus (the canal in Acne spots are caused by the obstruc- the skull through which the nerve pass- tion of hair follicles by sebum (the oily es from the inner ear to the brain). substance secreted by the sebaceous Usually, the cause of an acoustic neuro- glands). Bacteria multiply in the follicle, ma is unknown. However, tumours that causing inflammation. The change in affect the nerves on both sides of the sebum secretion at puberty seems to be head simultaneously may be part of a linked with increased levels of androgen condition known as neurofibromatosis. hormones (male sex hormones). Acoustic neuroma can cause deafness, Acne may be brought on or aggravated tinnitus, loss of balance, and pain in the by drugs such as corticosteroids and face and the affected ear. androgens. Exposure to certain chemi- Diagnosis is made by hearing tests fol- cals and oils in the workplace can also lowed by X-rays, CT scanning, or MRI. cause a type of acne. Surgery may be needed, but treatment 9 ACROCYANOSIS ACTINOMYCOSIS A with radiotherapy to shrink the tumour acroparaesthesia A medical term used is also effective. to describe tingling in the fingers or acrocyanosis A circulatory disorder in toes (see pins-and-needles). which the hands and feet turn blue, may ACTH The common abbreviation for become cold, and sweat excessively. adrenocorticotrophic hormone (also Acrocyanosis is caused by spasm of the called corticotrophin). ACTH is produced small blood vessels and is often aggra- by the anterior pituitary gland and stim- vated by cold weather. It is related to ulates the adrenal cortex (outer layer of Raynaud’s disease. the adrenal glands) to release various acrodermatitis enteropathica A rare corticosteroid hormones, most impor- inherited disorder in which areas of the tantly hydrocortisone (cortisol) but also skin (most commonly the fingers, toes, aldosterone and androgen hormones. scalp, and the areas around the anus ACTH production is controlled by a and mouth) are reddened, ulcerated, and feedback mechanism involving both the covered with pustules. Acrodermatitis hypothalamus and the level of hydro- enteropathica is due to an inability to cortisone in the blood. ACTH levels absorb enough zinc from food. Zinc increase in response to stress, emotion, supplements usually help. injury, infection, burns, surgery, and acromegaly A rare disease characterized decreased blood pressure. by abnormal enlargement of the skull, A tumour of the pituitary gland can jaw, hands, feet, and also of the internal cause excessive ACTH production which organs. It is caused by excessive secre- leads to overproduction of hydrocorti- tion of growth hormone from the sone by the adrenal cortex, resulting in anterior pituitary gland at the base of Cushing’s syndrome. Insufficient ACTH the brain and is the result of a pituitary production results in decreased produc- tumour. A tumour that develops before tion of hydrocortisone, causing low puberty results in gigantism. Acromeg- blood pressure. Synthetic ACTH is occa- aly is diagnosed by measuring blood sionally given by injection to treat levels of growth hormone, followed by arthritis or allergy. CT scanning or MRI. actin A protein involved in muscle con- acromioclavicular joint The joint that traction, in which microscopic filaments lies between the outer end of the cla- of actin and another protein, myosin, vicle (collarbone) and the acromion slide in between each other. (the bony prominence at the top of the acting out Impulsive actions that may scapula (shoulderblade). reflect unconscious wishes. The term is most often used by psychotherapists ACROMIOCLAVICULAR JOINT to describe behaviour during analysis Clavicle Acromioclavicular wrehpeonr tsth ef apnattaiseinets ,“ awctiss hoeust,” roart hebre ltiheafsn. joint Acting out can also occur as a reaction to frustrations encountered in everyday Acromion life, often taking the form of antisocial, aggressive behaviour. Scapula actinic Pertaining to changes caused by the ultraviolet rays in sunlight, as in actinic dermatitis (inflammation of the Humerus skin) and actinic keratosis (roughness and thickening of the skin). actinomycosis An infection caused by ACTINOMYCES ISRAELII or related actino- acromion A bony prominence at the mycete bacteria. The most common top of the scapula (shoulderblade). The form of actinomycosis affects the jaw acromion articulates with the end of area. A painful swelling appears and the clavicle (collarbone) to form the pus discharges through small openings acromioclavicular joint. that develop in the skin. Another form 10 ACUITY, VISUAL ADENOCARCINOMA of actinomycosis affects the pelvis in the corticosteroid hormones hydrocorti- A women, causing lower abdominal pain sone and aldosterone, normally produced and bleeding between periods. This by the adrenal cortex (the outer part of form was associated with a type of IUD, the adrenal glands). Excessive amounts no longer in use, that did not contain of ACTH are secreted by the pituitary copper. Rarely, forms of the disorder gland in an attempt to increase output affect the appendix or lung. Actinomy- of the corticosteroid hormones. Secre- cosis is treated with antibiotics. tion and activity of another hormone, acuity, visual See visual acuity. melanocyte stimulating hormone (MSH), acupressure A derivative of acupunc- is also increased. ture in which pressure is applied Addison’s disease can be caused by instead of needles. any disease that destroys the adrenal acupuncture A branch of Chinese med- cortices. The most common cause is an icine in which needles are inserted into autoimmune disorder in which the a patient’s skin as therapy for various immune system produces antibodies disorders or to induce anaesthesia. that attack the adrenal glands. Traditional Chinese medicine main- Symptoms generally develop gradu- tains that the chi (life-force) flows ally over months or years, and include through the body along channels called tiredness, weakness, abdominal pain, meridians. A blockage in one or more of and weight loss. Excess MSH may cause these meridians is thought to cause ill darkening of the skin in the creases of health. Acupuncturists aim to restore the palms, pressure areas of the body, health by inserting needles at appropri- and the mouth. Acute episodes, called ate sites along the affected meridians. Addisonian crises, brought on by infec- The needles are stimulated by rotation tion, injury, or other stresses, can also or by an electric current. Acupuncture occur. The symptoms of these include has been used successfully as an anaes- extreme muscle weakness, dehydration, thetic for surgical procedures and to hypotension (low blood pressure), con- provide pain relief after operations and fusion, and coma. Hypoglycaemia (low for chronic conditions. blood glucose) also occurs. acute A term often used to describe a Life-long corticosteroid drug treatment disorder or symptom that develops sud- is needed. Treatment of Addisonian denly. Acute conditions may or may not crises involves rapid infusion of saline be severe, and they are usually of short and glucose, and supplementary doses duration. (See also chronic.) of corticosteroid hormones. Adam’s apple A projection at the front adduction Movement of a limb towards of the neck, just beneath the skin, that the central line of the body, or of a digit is formed by a prominence on the thy- towards the axis of a limb. Muscles that roid cartilage, which is part of the larynx carry out this movement are often called (voice box). The Adam’s apple enlarges adductors. (See also abduction.) in males at puberty. adenitis Inflammation of lymph nodes. ADD The abbreviation for attention defi- Cervical adenitis (swelling and tender- cit disorder, more commonly known as ness of the lymph nodes in the neck) attention deficit hyperactivity disorder. occurs in certain bacterial infections, addiction Dependence on, and craving especially tonsillitis, and glandular fever for, a particular drug, for example alco- (see infectious mononucleosis). Mesen- hol, diazepam (a tranquillizer), or heroin. teric lymphadenitis is inflammation of Reducing or stopping intake of the drug the lymph nodes inside the abdomen may lead to characteristic physiological and is usually caused by viral infection. or psychological symptoms (see with- Treatment of adenitis may include anal- drawal syndrome), such as tremor or gesic drugs, and antibiotic drugs if there anxiety. (See also alcohol dependence; is a bacterial infection. drug dependence.) adenocarcinoma The technical name Addison’s disease A rare chronic dis- for a cancer of a gland or glandular tis- order in which there is a deficiency of sue, or for a cancer in which the cells 11