Smooth Muscle

- Labium is the Latin

word for "lip." It is a neuter noun, so the plural (for a pair of lips) is labia. But here is where usage can be confusing. There is also a Latin feminine noun for "lip"; singular labia, plural labiae. In anatomy, the neuter noun is used, so that the two sets of opposing lips of the vulva (even though this is strictly a female organ) are properly called the labia majora (the larger, external lips) and the labia minora (the smaller, internal lips). A related Greek verb is laphyssein, "to swallow greedily, to devour." It would seem that these words, all pertaining to lips, originated in imitation of the sound produced by lapping fluid into the mouth, labor is anotherword for parturition, the process of giving birth to a baby, and comes closer in meaning to the Latin noun labor, “a troublesome effort or suffering," than the common use of the word today as almost a synonym for ordinary work. The ancient meaning was implied in Jesus' entreaty, "Come unto me, all ye that labor and are heavy laden, and I will give you rest" (Matthew 11:28). laboratory sounds as though it was conceived as a name for any place where work was done. But this is not the sense in which the word was used in ancienttimes or asit is used now. A place where people work at plucking chickens or at hammering out horseshoes is not a laboratory. The word comes from the Latin elaborare, "to work out, as a problem, with great pains." An old English spelling was elaboratory and designated a place where learned effort was applied to the solution of scientific problems. We have simply dropped the "e." labyrinth is a near borrowing of the Greek labyrinthos, "a large structure with intricate passages intersecting each other." In Greek mythology, the Athenians were at one time sorely oppressed by Minos, the king of Crete, who exacted from them an annual tribute of seven young men and seven maidens. These unfortunate youngsters were condemned by Minos to be devoured by the voracious Minotaur, a monsterwith a man's body and a bull's head. That the Minotaur was fed but once a year accounts for his appetite. The victims were placed in a labyrinth where the monster roamed and from which there was no escape. A stop was put to this egregious practice by Theseus, the heroic son ofthe king of Athens. His ingenious plan was to use a clew, "a ball ofstring or yarn,” which was kindly furnished by Ariadne, King Minos' daughter, who had fallen in love with Theseus. By unwinding the thread along his path, Theseus could readily find his way out of the labyrinth after killing the Minotaur. This explains our use of “clue" for whatever leads to the solution of a problem. In anatomy, "labyrinth" designates the lateral mass of the ethmoid bone and also the internal ear, both of which contain intricate passages. laceration is a near borrowing ofthe Latin laceratio, "a tearing or a mangling." The word now serves for any cut incurred as an injury, but it retains its sense of forceful trauma. A cut made by a careful surgeon is an incision, not a laceration. lacertus is a Latin word that to the Romans meant both "a muscle" and "a lizard," presumably because of the fancied resemblance in shape. More specifically, the reference was to the biceps muscle in the upper arm. Now, in anatomy, "lacertus" designates the fibrous expansion or attachment of certain muscles, particularly the biceps brachii and the lateral rectus muscle ofthe eye. lacrimal originated in the Indo-European dakru, "a tear, as from a weeping eye." The same word was used by the Greeks. In archaic Latin this became dacruma, but in classical Latin the "d" was changed to “1" under Sabine influence, and to the Romans "a tear" was either lacruma or lacrima. The Old English derivative was taehher, whence the English "tear." In anatomy, we putthis together when we say, "The lacrimal duct conveys the tears." 129 lacteal larva An alternative spelling is "lachrymal," which was an aberration arising from the Medieval Latinists' custom of changing "c" to "ch" preceding an "r" (as in "pulchritude"); the "i" became "y" simply as a graphic variant. So, "lacrimal" is the correctspelling, even though poetically we persist in using "lachrymose" to describe a person given to weeping. lacteal refers to the fine, endothelial-lined lymphatic channels that convey fat-laden lymph from the absorptive intestinal mucosa. The appearance of such lymph suggests that of milk, hence the origin ofthe term in the Latin lacteus, "milky." lactic acid was originally discovered in sour milk (Latin lac, "milk"). lactose is the sugar (a disaccharide that on hydrolysis yields glucose + galactose) that naturally occurs in milk. For an explanation of the suffix "-ose," see glucose. lacuna is the Latin word for "a gap or hollow, a place where water tends to collect," such as a pit or pond. In anatomy, the term is used to refer to any similar configuration; for example, the tiny pits in compact bone. These minute apertures in bone, having been first described in 1691 by Clopton Havers (1657- 1702), an English physician and anatomist, are also known as "Haversian canals." The lining of certain ducts, notably the urethra, is marked by small pits or lacunae. lagophthalmos is an inability to completely close the eyelids. The Greek lagos means "hare," a rabbit-like animal distinctive in being bom with eyes open. lambdoid refers to whatever may be fancied in the shape of the Greek letter lambda (A), which looks like an inverted "V." Thus, the lambdoid suture of the skull and the lambdoid incision for gaining access to the epigastric viscera were so named. An occasional error in spelling or pronunciation is to omit the first "d." lamina is the Latin word for "a thin plate," and lamella is the diminutive form meaning "a little, thin plate." A host of anatomic structures incorporate these terms in their names. For example, the plate-like dorsal arches of the vertebrae are called laminae, and the operation whereby they are removed is laminectomy. lancet is a slightly shortened form ofthe French lancette, which was derived from the Latin lancea, "spear." A lancet is "a little spear." To lance a lesion, such as a boil, is to spear it. The Lancet, long one of the world's most respected medical journals, is said to have been given its name in 1823 by its founding editor Dr. Thomas Wakley (1795-1862) to assert his intent "to lance abscesses ofthe medical body politic," i.e., to expose charlatanism and shoddy medical practice, lanolin is a fatty subtance obtained from the wool of sheep. The name was concocted by combining the Latin lana, "wool," + oleum, "oil." As an emollient or unguent it is usually made up as a hydrous emulsion. It is commonly incorporated in cosmetic lotions purported to soften or "moisturize” the skin, lanugo is the Latin word for "down, meaning the small, fine hairs of plants." The lanugo of the fetus is the downy excrescence that appears aboutthe fifth month of gestation, laparotomy comes from the Greek lapara, "the soft parts of the body between the rib margins and the hips," i.e., the flanks or loins. This, in turn, is related to laparos, "slack, loose, or relaxed." The suffix comes from the Greek tome, "a cutting." "Laparotomy" was introduced as a term for an operation in 1878 by Thomas Bryant (1828-1914), an English surgeon. Purists insist that "laparotomy" should be used to designate only incisions in the flanks and not for those elsewhere in the abdomen, but the currency of usage has stifled their argument. Similarly, laparoscopy (+ Greek skopein, "to view") has been disdained in some circles as an improper term for looking into the abdominal cavity by means of an optical instrument, even though this instrument is inserted through the "soft parts" of the abdomen. This procedure was long known in the United States as "peritoneoscopy," but "laparoscopy," as the procedure is widely known and used in Europe and japan, has rapidly gained supremacy, larva is Latin for "mask or ghost." The Romans used the word to designate the specter ofthe dead, which they conceived as having the spirit but not the actual form of the living creature it represents. In this sense the term became applied to an early phase in the life 130 larynx laxative of an insect or parasite before its true form became apparent (which is known by the Latin word imago). Regressing to its figurative sense, we may make reference to a "larval" form of a disease when we mean an early, undefined phase in its development. The same can be said for “larval" ideas, larynx is a direct borrowing of the Greek term for "the upper part of the windpipe." This is related to the Greek verb lary[n]ggixd, "I bawl or bellow," from which the term laryngismus was derived, as an allusion to the crowing sound issuing from a spastic larynx, laser is an acronym, i.e., a word, preferably pronounceable, formed from initial letters or parts of a name or phrase, in sequence. "Laser" stands for Light Amplification by Stimulated Emission ofRadiation. A laser is a device that converts, within a medium of crystal or gas, incident electromagnetic radiation of mixed frequencies to a discrete, coherent, highly amplified emission of visible light. As such, the laser is a means of transmitting intense, focused energy, and it is thus used therapeutically for coagulation and ablation oftissues. Lassa fever was so named to commemorate the town in Nigeria where a missionary nurse was fatally stricken by the disease in 1969. latent is a slightly abbreviated form of the Latin adverb latenter, "secretly," and is related to the intransitive verb latere, "to lie hidden or concealed." Thus, latent syphilis is a "hidden" form of the disease, latex is the Latin word for "a liquid or fluid substance," especially that from a hidden source, such as water from a spring or sap from a tree (see latent). In botany, latex is the milky fluid extracted from certain plants, notably the rubber tree, which congeals on exposure to air or heat. In the laboratory, latex is any emulsion of fine particles of plastic substance that passively carry an adsorbed antigen and can be coagulated by certain constituents of serum. Thus, we have a "latex fixation test" for rheumatoid factor in serum and for human chorionic gonadotropin in urine, lathyrism is a morbid condition that may result from ingestion of seeds of certain leguminous plants of the genus Lathyrus, which includes a variety of peas. The toxic ingredient is (1-aminoproprionitrile that inhibits the enzyme lysyl oxidase. Symptoms include paresthesia, hyperesthesia, pain, and spastic paraplegia. The familiar "sweet pea" is a climbing herb (Lathyrus odoratus) cultivated for the fragrance of its varicolored flowers. The lesson here: "Inhale, but don't eat." laudable pus was a name once given to seropurulent effusion from a wound, in the mistaken beliefthatsuch discharge was a sign of healing. Only later was it recognized as a sign of infection. Laudable? Hardly. laudanum is an old designator of tincture of opium. Some scholars assertthatthe name is a derivative of the Greek ladonon, the resin obtained from an oriental shrub (not the poppy plant) that was known to the Persians as ladan. The claim is that this substance was confused with poppy juice, the source of opium. There is a more plausible, if not laudable, explanation. "Laudanum" was introduced into the pharmacopoeia by Theophrastus Bombastus von Hohenheim (1493-1541), a Swiss physician who named himself Paracelsus to indicate that he was on a par with, if not superior to, the renowned Celsus. He claimed he had a secret remedy (which may or may not have contained opium) that he considered laude dignum, "worthy of praise." It is curious to note that, much later, heroin (q.v.) was given its name because it was thought to be similarly laudable. laughing gas was the name given to nitrous oxide in 1800 by Sir Humphry Davy (1778- 1829), the remarkable English surgeonapothecary-chemist who investigated the curious psychotropic properties of the gas when it was inhaled. Davy went on to discover and isolate numerous elements, among them sodium, potassium, chlorine, and fluorine. Some say Sir Humphry's greatest discovery was his assistant, Michael Faraday. lavage comes from the Latin lavare, "to wash." "Gastric lavage" is another way ofsaying "a stomach washing." A lavatory, of course, is "a place for washing." laxative is derived from the Latin laxare, "to extend, widen, open, or release." In the sense of loosening or relaxing the bowel, the term was not used by the Romans but emerged in 131 laying on of hands lenticular the Middle Ages, perhaps because those were such costive times. laying on of hands (see king's evil) Lazarus syndrome encompasses the anxiety, depression, and sense of alienation sometimessuffered by survivors of cardiorespiratory resuscitation (Ann Intern Med. 1972;76:135). These are patients who have been brought back from the perilous brink of death. The allusion, of course, is to the brother of Mary and Martha, whom fesus raised from the dead (John 11:1-44). There is another unrelated biblical Lazarus, the diseased beggar shunned by the rich man who should have known better (Luke 16:19-31). From this Lazarus is derived lazaretto, an esoteric term for a hospital harboring victims of contagious disease or for a way-station, on land or afloat, to accommodate subjects of quarantine. The name was originally applied to a hospital maintained in Venice by the Church of Santa Maria de Nazaret. A translation of "Lazarus" is "God has helped." In more timely reference to the recent anthrax scare, a lazaretto also served as a facility for fumigating letters supposedly contaminated when written by persons known or suspected of being afflicted by contagious disease. lecithin comes from the Greek lekithos, "the yolk of an egg." This name for the mono-aminemonophosphatide was suggested by its early discovery in carp eggs. Its Greek origin would indicate the "c" in "lecithin" should be pronounced as "k," yet almost invariably it is given a voiceless fricative "s" sound. leech is the common name for a bloodsucking worm ofthe class Hirudinea, but it also was once used to designate a physician. In fact, the latter meaning came first, being derived from the Old English leece, "one who heals." Today, in Iceland a physician is a laeknir, in Finland a laakari, and in Sweden a lakare. The Dano-Norwegian is laege, the Polish is lekarz. The bloodsucking annelid worm, in bygone days, was used therapeutically, the idea being thatthe worm would consume corrupting substances from an inflamed lesion. Hence, the worm was give the name of "the healer" (Ann Intern Med. 1988; 109:399). Still later, "leech" became an epithet for a person who clung to and extracted sustenance from another. In days of yore, a "leechbook" was a manual of empiric remedies. Legionella is a genus of gram-negative aerobic bacilli capable of causing a pneumonia-like disease in man (legionellosis). The disease was first recognized and its cause discovered consequent to an outbreak that occurred among delegates to an American Legion convention in Philadelphia in 1976. The organisms proliferated in a contaminated airconditioning system of a large hotel. leiomyoma is contrived by linking the Greek leios, "smooth," + mys, "muscle," + oma, "swelling"; hence, "a Smooth Muscle tumor." Such tumors commonly occur in the muscular wall of the uterus and were, and sometimes still are, mistakenly called "fibroids." lemniscus is an almost direct borrowing of the Greek lemniskos, "a woolen ribbon or bandage," related to lemnos, "wool." In anatomy, a lemniscus is a band or bundle of neural fibers. lens is the Latin word (the genitive is lends) for the bean-like seed that we call "lentil." The only lens familiar to the ancients was that of the eye, and itwas given the name ofthe bean because ofitssize and shape; itstransparency had nothing to do with its naming. For those well acquainted with the lens ofthe eye but unfamiliar with lentil beans, examine the beans on your next visit to a grocery; you'll see the allusion is apt. The Greek word for the lentil bean is phakos, and by the same analogy that has been applied to the Latin lens, we have phako- as a combining form pertaining to the lens ofthe eye. Aphakia is an absence of the lens. Oddly, a phakoma is a minute, pale tumorseen microscopically in the retina in cases of tuberous sclerosis; also it is the term applied to a patch of myelinated nerve fibers seen in the retina in neurofibromatosis. Other terms include the misspelled phaco-, as in phacocele (+ Greek kele, "hernia"), denoting a dislodged, misplaced lens. lenta is the feminine form ofthe Latin adjective meaning "slow or sluggish." Subacute bacterial endocarditis was once known as "endocarditis lenta" because of its typically slow, lingering course. lenticular can describe whatever is shaped like a lentil bean (see lens), particularly the nucleus 132 lentigo leukoplakia found in the corpus striatum of the brain. It has nothing to do with the lens ofthe eye and was so named simply because ofits shape. lentigo is the Latin word for "freckle," related to the Latin lens, lentis, the legume bearing the small flattened bean we call "lentil." Indeed, what the dermatologist calls "lentigo" looks a lot like a freckle. It is a small, brown spotin the skin, resulting from the deposition ofmelanin pigment by an active focus of melanocytes near the basal layer of the epidermis. But to the dermatologist there is an important distinction. A freckle comes from exposure to the actinic rays of the sun, whereas lentigines (the plural) can be the result of various other causes. Conversely, a patch of white, depigmented skin is called vitiligo, a term derived from the Latin vitium, "a blemish or defect." To vitiate is to defile or make faulty. Incidentally, the suffix -igo, of Latin origin, once was used in a number of terms denoting conditions of disease in man, animals, plants, and even metals. Those medical terms that have survived are mostly related to dermatology, e.g., lentigo, vitiligo, intertrigo, and impetigo. Surviving terms related to other systems are vertigo and, as a slight variant, lumbago. leontiasis is a rare form of hyperostosis, occurring as a fibrous dysplasia in younger persons or as a feature of Paget’s disease of bone in the elderly, wherein the facial bones enlarge, giving the victim a countenance suggesting that of a lion. Leo, leonis is Latin for "lion." Beethoven is depicted in his later years as having a somewhat leonine countenance, and it has been suggested the great composer might have been a victim of Paget's disease, which also could have contributed to his deafness. leprosy comes from the Greek lepros, "scaly, rough, or mangy," hence, "the scaly disease." Gerhard Hansen (1841-1912), a Norwegian physician, correctly described the causative organism, Mycobacterium leprae, and the condition is now properly known as Hansen's disease. In ancient Greece, what we now know as leprosy probably did not exist. The "scaly disease" ofthe Greeks more likely was psoriasis. Aretaeusthe Cappadocian described leprosy accurately in the second century A.D., but he called it "leontiasis" because of the facial deformity. There then followed a confusion ofnames, and in the translation ofArabic writings the Greek lepra became attached to what is now recognized as Hansen's disease. The term "leprosy," then, doubly deserves to be abandoned, not only because of its unjust connotation of despicableness, but also because it has been misplaced nosologically. lepto- is a combining form taken from the Greek leptos, "fine, slender, or delicate." Thus, the leptomeninges (+ Greek meni[n]gx, "membrane") are the thin, delicate membranes, comprising both the pia and the arachnoid, that envelope the brain and spinal cord. Leptospira (+ Greek speira, "coil") is a genus of finely coiled spirochetes, lesbianism (see tribadism) lesion comes from the Latin laesio, "an attack or injury," which is related to the verb laedere, "to strike, hurt, or wound." lethal (see lethargy; also mortal) lethargy is a state of overpowering apathy or drowsiness. The term is taken from the Greek lethargos, "forgetful." In Greek mythology, Lethe was the name of a river that flowed in the netherworld of Hades. The souls of the dead were obliged to drink of its water and so become oblivious of everything said or done during theirspan on earth. One might assume thatthe word lethal, meaning deadly, was of analogous origin. Not quite. "Lethal" is from the Latin letum, meaning "death or destruction." The "h" got put in the English word in the 17th century because of confusion with the Greek lethe, "oblivion." Our word, then, should be "letal," but no one would recognize it as such. leuk-, leuko- is sometimes spelled "leuco-" (although “k" is preferred to "c") and is a combining form, usually a prefix, taken from the Greek leukos, "white," and also "light, bright, brilliant, and clear." The apostle Luke, patron saint of physicians, owes his name to the same source. leukemia is marked by neoplastic proliferation of any one of the species of leukocyte. The term combines leuko- + Greek aima, "blood." leukoplakia is characterized by white patches or plaques on a mucous membrane (leuko- + Greek plakoeis, "flat, broad"). 133 leukorrhea ligament leukorrhea is a white vaginal discharge (leuko-

• Greek rhoia, "a flow”). leukotrienes constitute a class of biologically active substances formed from arachidonic acid by the lipo-oxygenase pathway. They are so called because they act on leukocytes and contain three or more double bonds. levarterenol is also known as norepinephrine and marketed as "Levophed." It is the l- (for levo-) isomer (and the pharmacologically active form) of the chemical mediator liberated by mammalian postganglionic adrenergic nerves. levator comes from the Latin levare, "to lift." There are-a number of levator muscles in the body, and they all serve to lift whatever structure into which they are inserted. Muscles that lower attached structures are called depressors, a term derived from the Latin depressus, the past participle of deprimere, "to press down" (from de-, "down from," + primum, "above all"). levo-, lev- are prefixes taken from the Latin laevus, "on the left side." Purists insist "levo-" be spelled “laevo-," and they are right insofar as the term has nothing to do with the Latin lev- (related to "lifting") or lev- (related to "smoothness"). levulose is the name given by Claude Louis Berthollet (1748-1822), a French physician and chemist, to fructose (the sugar of fruits) because, in crystalline form, it caused polarized light to be rotated to the left, (see glucose) L-forms are pleomorphic, poorly stained organisms found in cultured colonies of various bacteria. They are aberrant derivatives ofthe parent organisms—not contaminants—and most will eventually revert to their original forms. The initial "L" is taken from the Lister Institute in London, where the nature of these aberrant forms was first reported in 1935. libido is the Latin word for "desire, longing, fancy, lust, or rut." In psychoanalysis the term is applied to the motive power ofthe sex life; in Freudian psychology, to psychic energy in general. lichen is a near borrowing of the Greek leichen, "a tree moss." In botany, a lichen is a compound plant composed by symbiotic union of a fungus and an alga, and it grows as an excrescence on rocks and trees. The term was used by the Greeks in reference to a blight or canker on olives, and hence came to be applied to various skin eruptions, probably most often ringworm. Now, the medical term is used almost exclusively as part of lichen planus (the second word is Latin for "flat"), an inflammatory skin or mucosal disease characterized by an excrescence of flat, white plaques. licorice is a confection and has little to do with medicine except that it is sometimes used as a flavoring agentto disguise the disagreeable taste of an active ingredient, as in cough syrups. Licorice is a leguminous plant, Glycyrrhiza glabra, and its name comes from the Greek glyky[s], "sweet," + rhiza, "a root," therefore, "the sweet root plant." In Late Latin the initial "g” was dropped to form liquiritia, and in Middle English this became lycorys. Incidentally, everyone thinks of licorice as being black. The black color is charcoal powder added only by confectional convention and has nothing to do with the flavor. A person who eats a lot of licorice might, to his dismay, pass a black stool, simulating melena. A candy-conscious doctor can be reassuring. lienteric refers to a type of diarrhea wherein the feces contain particles of undigested food, indicating rapid passage through the gut. The word is a combination of the Greek leios, "smooth," + enteron, "the intestine”; thus, “a slippery gut." Obviously, "lienteric" should be spelled "leinteric," but it isn't. And it has nothing to do with lien, Latin for "spleen." ligament is derived from the Latin ligare, "to bind or tie," and refers to the tough bands of connective tissue by which various structures are bound together orsupported. A ligature is something used as a tie, especially in surgery, and to ligate is to tie. Oliver Wendell Holmes, the 19th-century Boston savant, wrote in his Medical Essays, "I would never use a long word where a short one would answer the purpose. I know there are professors in this country who 'ligate' arteries. Other surgeons only tie them, and it stops the bleeding as well." The word "obligation," in the sense of a pledge, comes from the Latin ob, "on account of," + ligare, and thus means whatever one is bound to do for a particular reason. Another related word is "religion," which can 134 lily-livered lithotomy be viewed as a bond or pledge. To return to things medical, an obligate parasite is one that is so bound that it cannot live apart from its host, while a facultative (Latin facultas, "opportunity, feasibility") parasite can choose its environment and still exist by adapting to varying conditions. lily-livered is a fanciful term for timidity or cowardice. The liver was once believed to be the seat of passion, and lack of courage was attributed to hepatic ischemia. Shakespeare wrote of cowards "with livers white as milk." limbus is the Latin word for "fringe, hem, or border." Thus, the limbus of the cornea is the border where it joins the sclera. In early Roman Catholic theology, limbo was a supposed place, neither hell nor heaven, that was the abode of infants who died without baptism and ofthe righteous who died before the coming ofChrist. liminal is derived from the Latin limen, "threshold." As in "lumen" and "luminal," the second vowel ofthe derived adjective changes from "e" to "i." A liminal stimulus is just barely perceived by the senses, and a subliminal stimulus is "below the threshold" and not perceived at all. To eliminate is to discard "beyond the threshold," and whatever is preliminary, as, for example, a tentative diagnosis, is something considered "before crossing the threshold." linea is the Latin word for "line, string, or thread." In anatomy, the linea alba is the longitudinal streak of white fibrous tissue between the rectus abdominis muscles. To the Romans, the linea alba or "white line" was the mark made by lime or chalk across a track behind which chariots lined up for the start of a race. lingua is Latin for "tongue." The verb lingere means "to lick or lap up." To pronounce the Latin word is almost to imitate licking with the tongue. For the Greeks, "to lick" was leichein, also an imitative sound. A related word is "language," the utterance of which requires an active use of the tongue. A colloquial term for the spoken word, especially that peculiar to a certain group, is "lingo," recorded in English as early as 1600. lingula is the diminutive of the Latin lingua and used in anatomy as a term for anything shaped like a little tongue, e.g., the projection from the lower portion of the upper lobe of the left lung. liniment comes from the Latin linere, "to smear." In ancient practice, a linimentum was a thin, liquid ointment applied to the skin as an anodyne or counter-irritant, in the manner that a liniment is used today, lipid is any fatty substance (see lipo-), insoluble in water and soluble in common organic solvents. lipo- is a combining form taken from the Greek lipos, "animal fat or vegetable oil." lipofuscin is a lipid-containing granular pigment observed in various tissues and often attributed to cellular senility. It is sometimes called "wear-and-tear pigment." The name was contrived by hybridization of the Greek lipos + the Latin fuscus, “dark brown," because of its color. The latter Latin term gives a clue to the origin of "obfuscate," meaning to muddy up or make murky, (see fuchsin) lipolysis is a dissolution of fat (lipo- + Greek lysis, "a loosening"). liter is the American spelling ofthe French litre, proposed in 1793 as a convenient unit of capacity, being that of a cubic vessel measuring 10 centimeters on a side or, more accurately, the volume occupied by 1 kilogram of pure water atits temperature of maximum density and under standard atmospheric pressure. The term is an adaptation oilitron, an old obsolete French measure of capacity. This came from the Late Latin litra and the classical Latin libra, a unit of weight approximating 12 ounces. Twelve ounces compose one pound according to the troy or apothecary scale (q.v.) (16 ounces in the avoirdupois scale), and this accounts for "lb." as an abbreviation for "pound," taken from the Latin libra. litho- is a combining form taken from the Greek lithos, "stone." Cholelithiasis (Greek chole, "bile") is the condition wherein stone-like concretions form in the gallbladder, lithotomy is the operation of "cutting for the stone" (litho- + Greek tome, "a cutting"), originally applied to incision ofthe urinary bladder. Hippocrates, in his famous Oath, required his disciples to forswear "cutting for the stone," leaving that practice to "such as are craftsmen therein," presumably meaning urologists. 135 lithotripsy -logy lithotripsy (see sassafras) litmus comes from the Old Scandinavian Utmost, “dye moss," combining lit, "color or dye," + mossi, "a moss or lichen." Litmus is a coloring matter obtained from certain lichens and exhibits the helpful property of turning blue in an alkaline solution (pH > 7) and red in an acid solution (pH < 7). For convenience in the laboratory, the dye usually is impregnated in paper, a slip ofwhich is immersed in the fluid to be tested for alkalinity or acidity. "Litmus test" is now sometimes used figuratively for any trial to determine which of two opposing conditions might be valid. litter as the name for a simple device used to carry the sick or wounded comes by way of the French lit, from the Latin lectus, "bed." "Litter," with the different meaning of disorderly array, is related. At one time, litter was scattered straw used to prepare a bed for domestic animals. livedo reticularis is a mottled purple or dusky blue discoloration ofthe skin seen in hypoxic conditions (from the Latin lividus [see livid] + reticulum, "a network"). liver is the name of the largest solid organ in the body, generally acknowledged to be essential to life. Its name would seem to be related to the verb "to live." Perhaps it is. Its Old English predecessor was lifer. In German, the organ is Leber, and "to live" is leben. But scholars are notsure ofthe connection. It has been suggested that the Indo-European root word for the liver was yekurt, which became the Greek hepar (from which we have hepatic, hepatitis, hepatomegaly, and similarly derived forms), as well as the Latin jecur. The Latin term, oddly, has no descendent in Romance languages, being replaced by a Latin adjective ficatum, "stuffed with figs." It would seem the Romans combined liver and figs in a single dish. Ficatum became the Italian fegato, the Spanish higado, and the French foie, all meaning "liver." To the ancient Babylonians, the excised liver of a sacrificed animal was an organ of divination wherefrom they read all sorts of portents (see haruspication). Ironically, the ancient people had not an inkling of the truly astonishing metabolic function ofthe liver. In fact, the liver fell into disrepute when it was found not to be the wellspring of blood and lymph, an earliersupposition. It remained for Claude Bernard (1838-1878), the renowned French physiologist, to establish the liver in its rightful place as a vital organ, "a veritable laboratory of life," as he put it. It is appropriate that maladie du foie has become, in effect, the national disease of France. livid is a derivative of the Latin lividus, "the color of lead," and describes the bluish-gray hue of hypoxic blood as seen through the skin. Interestingly, the Latin lividus also means "jealous, envious, or spiteful." Presumably this is an allusion to the complexion of persons consumed by these emotions. Because an ashen complexion often clouds the face of a person beset by shocked wrath, we can say, "He was livid with anger." lobe comes from the Greek lobos, "a small, rounded projection," first applied to the floppy lower appendage of the external ear. This led to the Late Latin lobus and its diminutive lobulus (from which we have taken lobule). The lobes of the brain, lung, and liver were hardly mentioned as such in English until the 16th century. lochia is the fluid that seeps from the vagina during the first week or so after childbirth. The term is derived from the Greek locheia, "childbirth," being related to the Greek verb locheuo, "I bring forth or I bear." lockjaw (see trismus) locum tenens is a Latin phrase that literally translated means one who "holds the place" (from locus + tenere, "to hold") and refers to a doctor or other professional person who temporarily carries on the practice of an absent colleague. locus is Latin for "a place or site." The term is used in the names of various specific anatomic locations, particularly in the central nervous system. The plural is loci. -logy is a suffix taken from the Greek logos that can be variously translated as "discourse, reasoning, speech, study, thought, treatise, word," among other modes of expression. The familiar suffix is attached to a host of biomedical terms, and herein lies a common polysyllabic problem. For example, speakers or writers often use "symptomatology" when what they mean is "symptoms," or they use 136 loin lunatic "pathology" when what they mean is "disease" or "lesion." The problem is resolved when one asks, "Do I really mean 'the study ofsymptoms' or the symptoms themselves?" When one is about to use a term ending in "-logy," a good policy is to pause and think. loin (see psoas) long in the tooth is an old phrase descriptive of aging. It refers to the observation that the gums tend to recede with age, thus exposing more of the teeth. The expression has been used of both horses and people. This explains, too, the admonition: "Don't look a gift horse in the mouth." lordosis is an almost direct borrowing of the Greek lordos, "bent backward.” Such a posture results in an exaggerated anterior convexity of the lumbar spine. The term has nothing to do with a haughty or lordly bearing. The English "lord," incidentally, originally was hlaefweard, "guardian of the bread"; his lady was hlaefdige, "kneader of the bread." lotion (see ointment) louse as the name for a tiny pestiferous insect that infests animals, including humans, descends from a similar sounding Teutonic word that has cognates in most Germanic languages. The word is as ubiquitous as the bug. The plural, as with mouse/mice, is lice. This particular arthropod is of the genus Pediculus, a name taken from the Latin for "little feet." A familiar nickname is cootie, adopted by soldiers and sailors in World War I from kutu, a Malay name forthe pests. To be infested by lice is disgusting; hence, by extension, whatever is contemptible is "lousy." lozenge refers to the shape and not to the content or purpose ofa medication so formulated. The French losange means “diamond-shaped." The origin probably was the Old Gothic lausa, "a flatstone," + -inga, the Germanic suffix indicating "pertaining to." In Portuguese, lousa is a tombstone. Now, in pharmacy, a lozenge is a tablet, regardless ofshape, intended to be dissolved in the mouth for its topically soothing effect. lues is the Latin word for "infection, contagion, plague, or pestilence," and may have come from the Greek lua, "a dissolution." To the Romans, lues meant any sort of virulent, contagious disease. The more specific term lues venerea meant syphilis (q.v.), a disease usually acquired by the act symbolizing devotion to Venus, the goddess of love. "Lues,” despite its final "s,” is singular, not plural. There was a time when discreet doctors used "lues" at a patient's bedside in order to avoid saying "syphilis." lumbago is an old-fashioned term for any rheumatic pain in the region of the loins. An explanation of the suffix "-ago, -igo" can be found in the entry for lentigo. lumbar comes from the Latin lumbus, "the loin," and refers to anything pertaining to the lower paraspinal region. The lumbar vertebrae are situated between the loins. lumbricoid is derived from the Latin lumbricus, "a worm," and refers to whatever has the appearance of a worm. Lumbricus in zoology is the name given to a genus of annelids, including the common earthworm. Ascaris lumbricoides, the scientific name for a parasitic enteric worm, would seem to be a tautology. The Greek askaris means "an intestinal worm." The small, elongate lumbrical muscles in the hand and foot are so called because oftheir worm-like shape. lumen is Latin for "light," including the light that comes from a window or aperture. When sectioning a hollow viscus, one can see light through the opened space. Hence, "lumen" came to be a term designating that space. In the adjectival form luminal, the "e" becomes an "i." "Luminal" was once a trade name chosen for phenobarbital presumably as a reflection ofthe Greek phainein, "to bring to light." It must have seemed a bright idea to someone atthe time. lunatic as a term for a person mentally disturbed comes from the Latin luna, "moon." Such use relates to the old belief that mental disorder was a consequence of being "moonstruck." Another derivation would seem to be the slang word "loony." However, there is another explanation. The expression "crazy as a loon" refers not to the large, diving, flsheating bird but rather to the archaic "loon" that meant "a worthless, stupid fellow" and may have been derived from the Icelandic luinn, "beaten." One who had been beaten senseless might well act strangely. 137 lung lyslung may have originated in the Sanskrit laghu, which meant "light" in the sense of "without weight." It is likely thatthe ancients were impressed by the lightness oflung tissue in contrast to the density of other viscera. In almost all languages, the term for the lungs is related to the word for "lightness." For example, the Russian legkoe, "lunq," is related to legkii, "light." lupus is Latin for "wolf." The use of the wolf's name in the designation of various diseases reflects differing allusions. Lupus vulgaris (the latter word is Latin for "common") refers to tuberculosis of the skin wherein the infection appears to eat away at the skin, as by the gnawing of a wolf. Lupus Erythematosus, a skin characterized by inflamed and pigmented malar prominences, was so named because it seemed to impose on its victim a lupine or wolf-like countenance. lutein is a yellow pigment or lipochrome. The term comes from the Latin luteus, "mudcolored," lutum being Latin for mud or clay. The corpus luteum is the yellow body or nodule thatmarks the site ofa mature ovarian follicle from which an ovum has been discharged. luxation is derived from the Latin luxare, "to put out of joint or to dislocate." It is akin to the Greek loxos, "crosswise." A subluxation is a less-than-complete dislocation. Ifthe joint hurts, and you're not sure it is really dislocated, you can gravely pronounce the injury a "subluxation." Lyme disease is a multi-system affliction consequent to a tick-borne spirochetal infection. The vector is Ixodes scapularis ("deer tick"); the spirochete is Borrelia burgdorferi. The name given to the disease memorializes the first report of a cluster of cases recognized in the vicinity ofthe town of Old Lyme, Connecticut (Arthritis Rheum. 1977;20:7), an example of eponymic derivation. lymph is a slightly shortened version of the Latin lympha, "clear water, especially that found in flowing springs." Lympha is a pseudo-etymological formation influenced by the Greek rtymphe (wherein the "n" was exchanged for an "1"), the word for "a bride or marriageable girl." Nymphs were deities of lesser rank who presided over springs, lakes, and forests. The association seems to have been with a sense of moisture. In ancient anatomy, the lymphatic vessels were so named because, although they were thought to be veins, they were observed to carry a watery fluid rather than blood. The nodes intimately associated with these vessels were called lymphatic glands or, more correctly, lymph nodes. The idea of lympha became incorporated in the humoral system of pathology, and a supposedly cool, moist temperament became known as the phlegmatic or lymphatic type. There was a time when a sluggish disposition was attributed to an overgrowth of lymphoid tissues. A person so perceived was said to be in status lymphaticus. lymphocyte is the name given to certain mononuclear cells aggregated within lymph nodes, but also infiltrating other tissues, as well as observed in circulating blood. The term originated with Paul Ehrlich (1854- 1915), the famous German bacteriologist and immunologist. lys- is a combining form taken from the Greek lysis, “a loosening or setting free." The term is used as a prefix, as in lysozyme, a basic protein that functions as an antibacterial enzyme; as a suffix, as in hydrolysis, the breakdown or release of components of a substance by the addition of water (the H* going to one resultant part and the OH- going to the other); or by itself, as in the lysis of fibrous adhesions.

dacry- is a combining form that refers to tears or to tearing (both words pronounced with a long "e"), as in weeping. The term is an almost direct borrowing of the Greek dakry, "a tear." Thus, dacryadenitis is an inflammation ofthe lacrimal gland. -dactyl- is a combining form referring to a finger, or sometimes a toe, and is derived from the Greek daktylos, "finger." Syndactyly (Greek syn, "together") is the condition wherein adjacent digits are joined by a congenital web. Arachnodactyly is a term for abnormally long, spindly fingers or toes, (see arachnoid) daltonism is a term for the sex-linked inherited defect of red-green color blindness. It derives from the name ofJohn Dalton (1766-1844), a British physicist who wrote extensively on color blindness, with which he himself was afflicted. dandruff is usually plainly evident as a condition; as a word, its origin is obscure. The first syllable may relate to an archaic English dialect word for small scales of skin, hair, or feathers. The second syllable probably comes from the Old Norse hrufa, "scab." "Dander" seems to be a contraction of "dandruff." In any case, dandruff is probably the most frequent diagnosis evident by periodic physical examination of healthy persons, dartos is the name, as in tunica dartos, given to a layer ofSmooth Muscle fibers intermingled with the fascia enveloping the testicles in the scrotum. It is a borrowing of the Greek word for "that which is flayed." data is the plural (a point not always remembered by American speakers and writers) of the Latin datum, “a thing given," the neuter past participle of dare, "to give." In science, data are assembled as facts, statistics, or the like; one rarely encounters datum in reference to a single fact or statistic, but such use would be entirely proper, deadly (see mortal) deaf in Middle English was spelled (and pronounced) "deef." So, the old-timer who pronounces the word to rhyme with "reef" is not being comical; he is being archaic. The original Indo-European root likely was dheubh, "dull to perception." Curiously, our adjective "absurd" bears a relation to deafness. The Latin absurdus, "senseless or silly," is a combination of ab-, "from," + surdus, "deaf, unheeding." debridement is a French word that combines de, "not,” + brider, "to bridle,” thus literally an "unbridling." Originally the term was used for the process of cutting constrictive bands but later, in surgery, came to refer to the cutting away of injured or necrotic tissue. deceased is a delicate way of saying "dead." Not only is it delicate, itis used almostinvariably as a passive verb. No one with a civil tongue speaks of "deceasing" himself or anyone else. "Deceased" comes from the Latin decedere, "to go away, to depart." This is akin to referring to death as "a passing away." Demise is a delicate noun for death. Its origin is somewhat tortuous but probably goes back to the Latin demittere, "to drop, to send down." A worthy suggestion might be to leave "deceased" and "demise" to persons given to unctuous speech, such as morticians. Dead, even though a four-letter word, is perfectly respectable. deci- is a combining form subtracted from the Latin decimus, "a tenth." The decimal system is a numeration based on tenths. A deciliter (abbreviated as "dL") is one-tenth of a liter, or 100 milliliters. Incidentally, to decimate means to subtract by one-tenth. In the Roman army a harsh custom was to punish mutiny by executing one of every ten men in a rebellious unit. Uninformed writers or speakers have been known to mistakenly use "decimate" when they mean "annihilate", i.e., "reduce to next to nothing." decidua relates to the Latin verb decidere, "to fall away." Deciduous trees are those from which the leaves fall away in the chill of autumn, and deciduous teeth are those shed by youngsters in the normal course of development. In medicine, decidua is the name given to the mucosa of the uterus that "falls 63 decoction dendrite away" after parturition. The menstrual decidua is the hyperemic endometrium that is shed in the normal menstrual cycle. A decision incidentally, is made after all other options or possibilities are discarded. The late Chester Jones, long an esteemed clinician at the Massachusetts General Hospital, is often quoted as saying, "If you can't make a diagnosis, make a decision." decoction (see concoction) decrepit describes whatever is infirm or broken down by age or hard use. The word is an almost direct borrowing of the Latin decrepitus, "broken down," which, in turn, combines de-, "from," + crepare, "to make rattle or creak." decubitus is from the Latin verb decumbere, "to lie down,” and is related to the Latin cubitum, "the elbow." The Romans habitually rested on their elbows when reclining. Decubitus is a reclining position, usually further specified as, for example, "the left lateral decubitus." A decubitus ulcer is a bedsore, the consequence of pressure necrosis in a dependent part from lying in one position too long. Some related words are cubicle, a small chamber in which to lie down; cubbyhole, a small place to lay anything; incumbent, a state of lying in or occupying; and concubine, one who lies with another, decussation is from the Latin verb decussare, "to divide crosswise," i.e., in the form of an "X." The decussation of the anterior pyramids of the medulla oblongata is the crossing of fibers from one side to the other so as to form the lateral spinothalamic tracts, defecate (see feces) deferens (see vas) degenerate comes from the Latin degenerare, "to disgrace, to fall short of, or to be inferior to one's ancestors." The derivation is from de-, "down from," + genus, "the race.” In biology, a degenerated cell is one that has deteriorated in structure or function when compared with its normal counterparts ofthe "race." deglutition is a combination of the de-, "down," + the Latin glutire, "to gulp.” Now the term is used in the gentlersense ofsimply swallowing. A related word is glutton, dehiscence can describe any abnormal gaping or splitting of tissue but most often is applied to separation of one or more layers of a partially healed wound or incision. The term is taken from the Latin dehiscere, "to part, divide, gape, or yawn." dehydrate is a relatively recent hybrid term contrived from the Latin de, "out of," + the Greek hydor, "water." Whoever or whatever is dehydrated has been deprived of water, delirium is said to have been first used by Aurelius Cornelius, better known as Celsus, the celebrated Roman encyclopedist ofthe 1st century A.D. The term is from the Latin de-, "away from," + lira, "a furrow." Whoever is mentally confused or incoherent cannot plow a straight furrow and may be said to be out of his groove. deltoid refers to the shape of A (delta), the fourth letter of the Greek alphabet. Hence, in anatomy it can describe anything triangular in configuration. The Deltoid (Muscle)(s) at the shoulder is more or less triangular, delusion comes from the Latin deludere, "to dupe or deceive." The Latin ludere means "to play or to amuse oneself," and a ludio was an actor. One who suffers delusions is being misled by imaginary circumstances, dementia is the Latin word for "madness" and comes from a combination of de-, "out of," + mens, "the mind." Whoever is demented is out of his mind. In a now outmoded classification, one form of mental derangement often observed in younger persons was known as dementia praecox, the second word being Latin for "premature" (and the source of our word "precocious"). Praecox (prae-, "before," + coquere, "to cook") literally means "uncooked" or "half-baked." Dementia praecox is now recognized as schizophrenia or one of its variants, demise (see deceased) demulcent comes from the Latin demulcere, "to stroke lovingly or to caress," this being a combination of de-, "down," + mulcere, "to pet or to soften." The Romans used demulcere particularly for the soothing stroking of horses. In medicine, a demulcent is a soothing preparation, especially one topically applied to allay the irritation of inflamed surfaces, dendrite means "branched like a tree" and is derived from the Greek dendron, "tree." In anatomy the term refers particularly to the 64 dengue dhobie itch branching protoplasmic processes of nerve cells. In botany, a rhododendron (Greek rhodon, "rose") is an evergreen tree bearing rose-colored flowers, and a philodendron (Greek philos, “loving") is a climbing plant with evergreen foliage and a propensity to cling to trees. dengue is the name of an acutely painful, febrile illness endemic in the West Indies, the Middle East, India, and the South Pacific. It is also known as "breakbone fever." Its victims often exhibit contortions because of intense muscle and joint pains. One explanation is that the name originated in the Swahili word ki-dinga, "a sudden cramp or seizure." Another explanation relates to the Spanish denguero, which means "affected or finicky." Slaves in the West Indies were said to have called the disease "dandy fever," presumably because of the affected gait or postures of persons so afflicted. dental is taken from the Latin dens, "tooth or tusk," and refers to whatever pertains to teeth. The Latin densus means "hard, compact." Dentin is the principal substance of a tooth, surrounding the pulp and being covered by enamel. Dentate means "arranged like teeth"; the serrated mucocutaneous border atthe anus is a dentate line. deoxyribonucleic acid (see DNA) depilatory refers to an agent, usually applied as a cream, that removes unwanted hair. The word is derived from the de-, "away," + the Latin pilus, "hair." depressor (see levator) dermis comes from the Greek derma, "the skin." A related Sanskrit word is dartis, "leather or hide." When used alone, "dermis" refers to the corium or dense layer of connective tissue underneath the stratified squamous epithelium of the skin. As a combining form, derm- contributes to a host ofterms pertaining to the skin, such as dermatology (the science of the skin), dermatitis (inflammation of the skin), dermatome (an instrument for slicing the skin), dermatographia (a condition wherein gentle stroking induces a localized swelling that appears as a “writing" on the skin), and many others. desiccate comes from the Latin desiccare, "to dry up or to drain," this being derived from a combination of de-, "away," + siccus, "dry." The sicca complex (q.v.) is characterized by excessive dryness ofthe normally moist membranes of the eye and mouth. The French sec, "dry," particularly as it refers to wines lacking a sweet flavor, is a related word, desmo- is a combining form taken from the Greek desmos, "a band or fetter." Consequently, "desmo-" has come to refer to dense fibrous or connective tissue. Desmoid describes a dense connective tissue neoplasm, such as can occur in persons afflicted with Gardner's syndrome. Desmoplasia (desmo-

• Greek plassein, "to form or mold") is a pervasive growth of fibrous tissue, particularly thatinvesting certain neoplasms, desquamation (see squamous) detritus is the past participle of the Latin deterere, "to rub off or to rub away." Detritus, then, is that which is rubbed away and refers, as a medical term, to debris collected in or around degenerating or necrotic tissue, (see trituration) detrusor comes from the Latin detrudere, "to push down or to dislodge." The detrusor muscle ofthe urinary bladderserves to aid in the expulsion of urine. dexter is the Latin word for "right," as opposed to "left." As the combining form dextr-, it has been incorporated in numerous anatomic terms designating the right-sided component of various bilaterally symmetric structures. Because most people are naturally more facile with their right hands, dexterity has come to mean "skill or deftness." (see adroit) dextrin is an intermediate product of the hydrolysis ofstarch and is so called because of its dextrorotary ("turning to the right") effect on polarized light, dextrose is a colorless, crystalline hexose that exhibits a dextrorotary property. More specifically it is D-glucose, the "d" standing for "dextro-." (see glucose) dhobie itch is sometimes used as a nickname for tinea cruris, a pruritic fungus infection of the groin. Dhobie is the Hindustani word for "a washerman." More specifically and properly, "dhobie itch" refers to a contact dermatitis caused by hypersensitivity to the marking fluid (bhilawanol oil) used by native laundrymen in India. 65 dia- diastema dia is a busy combining form taken from the Greek preposition dia, which has many meanings, including "through, throughout, thoroughly, completely, across, and opposed to." It appears as a prefix in many truly Greek words and also has been used to lend a classical tone to many newly concocted words, diabetes is a direct borrowing ofthe Greek word for both a siphon and a compass, i.e., the device used to draw circles. The Greek verb diabainein means to straddle or stand with legs apart. The connection between a siphon and a compass is simply that both instruments have separated "legs.” Aretaeus the Cappadocian, a famous Greek physician of the 2nd century A.D., explained that diabetes as a disease was so called because its victims "passed water like a siphon." Polyuria has been long recognized as a cardinal symptom of diabetes. The common sort of diabetic urine is laden with sugar; hence the disease is diabetes mellitus, mellitus being Latin for "sweetened with honey." The urine of patients with the rare diabetes insipidus, on the other hand, while voluminous, is lacking in sugar and therefore tasteless or insipid (in-, "lacking," + a derivative ofsapientia, "taste or sense"), diagnosis is a direct borrowing of the Greek diagnosis, butto the Greeks this meant specifically "a discrimination, a distinguishing, or a discerning between two possibilities," in the sense of resolving or deciding. The word combines dia- in any or almost all of its meanings
• gnosis, "knowledge", as applied to the discernment of a particular disease, dialysis is a direct borrowing ofthe Greek word for "a loosening of one thing from another." It is almost exactly in that sense that "dialysis" is used in medicine as "a process ofseparating crystalloids or colloids in solution by the difference in their rates of diffusion through a semipermeable membrane" (Dorland's). diapedesis (d/a- + Greek pedan, “to leap") was used by ancient writers to refer to eruption of blood from wounds. In modern medical parlance, diapedesis refers to the escape of blood corpuscles through the discontinuous endothelium of intact vessels, particularly as this occurs in response to inflammation, diaper refers not to the shape or purpose of the familiar "three-comer pants" butto the fabric and its color. The word combines dia-, "thoroughly," + the Greek aspros, "white." In ancient times the fabric was of fine texture and pristinely white. diaphoresis is a Greek word used by ancient writers for "profuse sweating." It includes the Greek phorein, "to convey." Diaphoresis is a highfalutin way ofsaying "sweating." diaphragm is a near borrowing of the Greek diaphragma, "a partition," this being a combination of dia-, "across," + phragma, "a fence or wall." Certain ancient writers ascribed greatsignificance to the muscular diaphragm separating the chest from the abdomen, some even attributing to it powers of the mind. This explains the naming of the phrenic (Greek phren, "the mind") nerve that supplies the diaphragm, possibly because the diaphragm sits atop the spleen and kidneys, organs once thought to be the seat of emotions. (see phrenic) diaphysis incorporates the Greek physis, "growth." Originally the term referred to "the bursting of a bud" or "the point where a branch grew from a stalk." Later, in anatomy, "diaphysis" came to be applied to the shaft of a long bone, particularly as a growth center, in distinction to the epiphysis, a growth center atthe articular end of a long bone. diarrhea is an almost direct borrowing ofthe Greek diarrhoia, "a flowing through," which incorporates the Greek rhein, "to flow." The ancients used the term, as we do, in reference to excessive, watery evacuation from the bowel. diastase is a word coined in the 19th century as the name for a substance (later identified as an enzyme) capable of breaking down orseparating starch into its component sugars. It was taken from the Greek diastasis, "a standing apart." Because diastase was thought of as the prototype of an enzyme, the lastthree letters, "-ase," came to be a suffix designating an enzymatic property, (see -ase) diastasis is still used in its original Greek meaning when applied to a separation ofportions of bones or muscles normally attached. diastema is a direct borrowing of the Greek word that means "a standing apart." In biology, diastema refers to the zone of modified 66 diastole digitalis protoplasm atthe equator of a cell that exists previous to mitotic division ofthe cell. In dentistry, diastema is a gap between teeth that normally abut closely, especially an exaggerated space between the incisor and canine teeth in the upper jaw. The condition was evident in the dentition of certain of the Spice Girls, a British rock band, and perceived by devotees as so "cool" thatthey flocked to dentists to have their teeth parted in imitation, diastole is a direct borrowing ofthe Greek word meaning "a distinction or difference" and is a combination dia-, "apart," + stellein, "to put." "Setting apart" implies introducing or expanding a pause between a sequence of circumstances or events. It is in this sense that "diastole" came to be, in physiology, the name for the period of relaxation and dilatation of the heart muscle between systolic contractions. diathermy is a contrived term incorporating the Greek therma, "heat," intensified by the prefix dia-, thus referring to "penetrating heat." diathesis is a Greek word meaning "an order of arrangement," particularly in the sense of "a disposition." Ancient writers conceived that certain persons, because of their make-up or temperament, were particularly disposed to certain diseases. We use the term in much the same way when we refer to a predisposition as, for example, in "hemorrhagic diathesis." dichotomy is taken from the Greek dikhotomos, "divided," this being a combination of dicha, "in two," + tome, "a cutting." A dichotomy, then, results in two equal parts or a pair. In biology, the term refers to branching equally to become a pair. Used figuratively, "dichotomy" means a division into two usually contradictory parts or opinions, dicrotic is derived from the Greek di-, "two or twice," + krotein, "to strike." The term has been applied to a doubly peaked pulse wave. Anacrotic (Greek ana-, "upward") means the secondary impulse is on the ascending limb of the pulse wave; catacrotic (Greek kata, "down") means the secondary impulse is on the descending limb, dicumarol (see warfarin) diet comes from the Greek diaita, "a way of living or a mode of life." Originally the term was used for a hygienic regimen generally; only later it was restricted to a mode of eating considered conducive to good health. Incidentally, this is quite distinct from "diet" as the name for an assembly or parliament, which is taken from the Latin dies, "day," implying that a formal meeting is held on an appointed day. digastric is the name of a muscle in the anterior neck that depresses the mandible and elevates the hyoid bone. It is so called because it has two bellies, its name coming from the Greek di-, "two," + gaster, "belly." Obviously, despite its name, the muscle has nothing to do with the stomach. digestion is derived from the Latin digerere, "to arrange, sort out, or distribute." Medieval chemists used the term in the sense of “dissolving." In the 17th century a device was introduced whereby bones could be softened by cooking under pressure, and this was called a “digester." The early physiologists borrowed the term in the belief that ingested food was treated in the stomach in a manner similar to digestion as carried out in the chemist's laboratory. As it turned out, they may have been closer to the mark than they might have guessed. digit is a contraction of the Latin digitus, "a finger or a toe." A digitation is a finger-like process, and to interdigitate means to appear as interlocking fingers. "Digit" as a term for a number came from the custom of counting on one's fingers. Our normal allotment of ten fingers accounts for the decimal system we use for numbering, as well as for the metric system based on ten. (see finger) digitalis comes from the Latin digitus, "finger." The allusion is to the tubular blossoms ofthe plant whose dried leaves, when pulverized, provide the drug. The shape ofthe flowersuggests the empty finger of a glove. In part, this explains the plant's common name, "the foxglove.” But why the “fox"? No one really knows. By curious coincidence, "digitalis" was proposed as the Latinized name for the plant in the 16th century by Leonhard Fuchs (1501-1566), a German botanist whose surname is German for "fox.” Apparently he chose digitalis, a Latin way of saying "pertaining to the finger,” because the common German name for the plantis Fingerhut, which 67 dilate dissect means, literally, "a finger hat" or thimble. But we are still left wondering why the foxglove was so called as early as the 11th century. dilate is a verb meaning "to enlarge or expand” and is taken from the Latin dilatare meaning the same and derived from di-, dis-, "apart," + latus, "wide.” Often in medical parlance and writing "dilation" and "dilatation" are used more or less interchangeably. More precise usage calls for "dilation" as the performance and "dilatation" as the result. The instrument used to accomplish the task is commonly called a "dilator." But here the most persnickety word mavens step in to insist that "dilation" and “dilator" are wrongly formed from the Latin (the first "-at-" being part ofthe word and not contributing to the suffix "-tion," indicating an action). Therefore, we are instructed to always use "dilatation" in reference to either the procedure or its result and "dilatator" for either the instrument orthe operator. To consistently use "dilatation" won't be difficult, but, the sticklers notwithstanding, it is doubtful "dilatator" will play in Peoria. dimercaprol (see BAL) diopter originated in the Greek dioptra, an early optical instrument used for accurately measuring heights and angles. "Diopter" later was adopted as a name for the unit of refractive power of lenses, expressed as a reciprocal ofthe focal length in meters. diphtheria was given its name from the Greek diphthera, "a prepared hide or leather," by Pierre Bretonneau, a French physician, in the 1820s. The allusion is to the parchment-like membrane in the throat characteristic of the disease. Diphtheria was known to the ancient Greeks and dreaded because of the high rate ofmortality among children, butthey did not call it by that name. To them it was the "Egyptian disease" or "Syrian ulcer," yet another example of blaming a malady on those from another country. diplo- is a combining form taken from the Greek diploos, "double or two-fold." diplococcus is the name given to a bacterium that looks like a pair of tiny berries (Greek kokkos, "berry"). diploidy is the normal state of having paired sets of homologous chromosomes in somatic cells, (see -ploid) diplopia was contrived as a combination of diplo- + the Greek opsis, "vision," a term for disunited visual images that first appeared in print in the early 19th century, dipsomania links the Greek dipsa, “thirst," + mania, "madness." The term first appeared in English in the mid-19th-century to mean "an uncontrollable craving for drink," specifically referring to alcoholic beverages, and deemed a form ofinsanity, dis- (see dys-) disease comes from the Old French desaise, a combination of des-, "away from," + aise, "ease." In its early use, the term referred to any tribulation that disturbed one's ease. Only later did "disease" acquire its restricted medical sense. disk is a slightly abbreviated version of the Greek diskos, "a circular, flat stone," which the Greeks were much given to hurl. Sometimes the diskos had a hole in the center, either for a strap by which to swing it or so it could be used as a quoit (a doughnut-shaped object to toss at a peg). The discus (Latin counterpart) throw is still a feature ofmodern Olympic games. "Disk" or "disc" now refers to any circular, plate-like structure as, for example, the intervertebral disk, disorienteddescribes a person who has lost his sense of direction or relation to his surroundings. The term comes from a combination of the Latin dis-, "deprived of," + oriens, “the rising sun or the direction of east," the latter being a present participle of oriri, "to rise." To say a person is disoriented means, literally, "He doesn't know which way is east," but in more familiarterms, "He doesn't know which end is up." dispensary comes from the Latin dispensare, "to weigh out." Originally the term was applied to a place where medicinal agents were measured and distributed. Later, it came to mean a place where the sick or injured were treated but not confined as inpatients. In the past, outpatient departments often were called "dispensaries." dissectisfrom the Latin dissecare, "to cut apart," this being a simple combination of dis-, "apart," + secare, "to cut." An anatomic dissection, then, is "a cutting apart" of a body or a part thereof for the purpose of identifying <58 disseminate -dontal and examining its components. Surgical dissection is a necessary preliminary to resection. (see resection) disseminate (see semen) distal (see proximal) distill is derived from the manner in which vapor from a heated liquid is condensed and collected, drop by drop. The word is a combination of the Latin de-, "from," + stilla, "a drop." To instill originally meant to introduce a liquid drop by drop, diuresis combines the Greek dia-, "thoroughly,"
• ourein, "to urinate." There is a distinction between stimulating the excretion and flow of urine from the kidney and stimulating the contraction ofthe urinary bladder in order to cause its evacuation. By common acceptance, a diuretic agent is understood to be that which promotes the formation of urine by the kidney. An example, among others, would be chlorothiazide. On the other hand, bethanechol, which induces Smooth Muscle contraction, is a bladder evacuant, not a diuretic. At one time a decoction of dandelion leaves was used as a diuretic, hence the French name for the weed: pissenlit, literally "piss in bed." diurnal (see journal) diverticulum is a direct borrowing ofthe Latin word for "a bypath orsmall wayside shelter," coming from the verb divertere, "to turn aside." The suffix "-culum" implies the diminutive and indicates that a diverticulum is subsidiary to the main channel. It is importantto remember that "diverticulum" is the Latin neuter singular and that "diverticula” (not "diverticuli" or "diverticulae") is the neuter plural, a point that many careless speakers and writers seem to ignore, dizzy (see vertigo) DNA are initials now in common parlance and nearly everyone knows they stand for deoxyribonucleic acid, the substance that conveys genetic information. Johann-Friedrich Miescher (1844-1895), a Swiss worker particularly interested in the chemistry of cell nuclei, in 1870 managed to extract nearly pure DNA from spermatozoa ofsalmon, cells with exceedingly large nuclei. Miescher had no idea of the significance of his accomplishment. DNA consists of two long chains of nucleotides, twisted in the shape of a double helix and made up ofsequences of complementary pyrimidine base pairs: adenine and thymidine or cytosine and guanine. Adenine was originally isolated in 1885 from a nucleic acid found in beef pancreas, hence its name indicating a product of a gland (see adeno-). Cytosine (1894) is a name derived by linking cyt- + (rib)os(e) + -ine. Guanine was identified in bird droppings in 1844 and named from Spanish guano, "bird dung," taken from the Quechua huanu. Quechuan is an Incan language, and vast deposits of guano were discovered by Spaniards on islands off the coast of Peru. Thymine was given its name in 1894 when first isolated from the thymus glands of calves. doctor is taken from the Latin docere, "to teach." In years past, "doctor" was a title of courtesy and respect bestowed on a learned man. Later, it became the title accorded a holder of the highest academic degree. Meanwhile, "doctor" acquired, mainly among speakers of English, a specifically medical connotation. Probably this was because, of all learned scholars, only members of the medical faculty were figures familiar to the public at large. In no language other than English is a practitioner of medicine commonly referred to as a "doctor" (see iatr-) or is "doctor" used as a verb, meaning “to treat or alter." (see leech) dol is an arbitrary unit used to express intensity of pain. It is an elision of the Latin dolor, "pain." dolicho- is a combining form derived from the Greek dolichos, "long." Thus, dolichocephalic refers to a long head, and dolichocolon is an unusually long and redundant large intestine. doll's eyes in medical parlance is an expression that describes peculiar movement of the eyes in patients with certain types of metabolic coma, notably in hypoglycemia and hepatic encephalopathy. Moving the head from one side to the other will elicit abrupt movement ofthe eyes to the opposite side, suggesting the mechanical movement of doll's eyes, a sign of cortical depression with intact brainstem connections. -dontal (see tooth) 69 DA; PIF (Dopamine ; Prolactin Inhibiting Factor) drosophila DA; PIF (Dopamine ; Prolactin Inhibiting Factor) is an immediate metabolic precursor of epinephrine and norepinephrine, hence  important in central sympathomimetic actions. Sometimes called by its nickname "dopa," it has nothing to do with "dope.” It is merely a somewhat unfortunate acronym for 3,4-dihydroxyphenylethylamine. dope comes from the Dutch doop, meaning "a sauce or viscous liquid." The term became applied to narcotics because raw opium when heated becomes a thick liquid. Later, any substance having a numbing or stupefying effect became known as "dope." By extension, a person afflicted with a narcotic effect was called, in slang, "a dopehead" or simply "a dope." But there is more to the vagaries of this little word. Unscrupulous racehorse promoters found they could often ensure the outcome of a race by giving a drug to the mount pre-selected for winning. Anyone privy to this illicit information was said to have "the inside dope." Soon, any worthwhile intelligence came to be called "the dope." doppler describes a recordable effect ofsound or ultrasound waves when they emanate from or are directed at a moving object. The technique has been applied to medical diagnosis, especially in determining the extent and direction of blood flow within a given vessel. The term is taken from the name of Christian Doppler (1803-1853), an Austrian mathematician who was the first to explain why, for example, the pitch of a locomotive whistle is higher when the train is approaching the listener than when the train is speeding away. dorsum is Latin for "back.” Thus, the dorsum of the hand or foot is the "back" ofthat part, opposite the palm or sole. The adjective dorsal is understood to pertain to the back of any part, but especially to the back of the thorax. The dorsal vertebrae are the thoracic vertebrae. "Dorsal" also is used to mean "posterior,” as in the dorsal roots ofthe spinal nerves. Incidentally, to endorse a check is to sign one's name on the back ofthe document, dose is said to have had its origin in the postulated Indo-European root do, "to give." A descendent is the Greek dosis, "that which is given." A related word is the Latin donare, "to bestow," and from this we derive "donate." A dose, then, is the "giving" of a specified amount of a medicine. douche is the French word for "a shower-bath" and can be traced to the Latin ductus, the past participle of ducere, "to lead." A douche, then, is a stream of water or watery solution directed to a body part or cavity for the purpose of cleansing. Down syndrome (see mongolism) dram is an almost forgotten unit of measure. It came originally from the Greek drachme, a coin approximately equivalent to a Roman denarius. The coin also was used as a weight, and later a "drachma" or dram became oneeighth of an ounce as an apothecary's weight (but one-sixteenth of an avoirdupois ounce). Before adoption of the metric system, a dram of fluid was commonly taken to be one teaspoonful (nearly equivalentto 5 mL). One tablespoonful (approximately equivalent to 15 mL) is one-half a fluid ounce. The use ofteaspoons and tablespoons for prescribed doses of liquid medicines is common because these utensils are readily available for measurement in most households. Ounce comes from the Latin uncia, "a twelfth," this being one-twelfth of a Roman libra or pound (hence the abbreviation "lb." for pound). One must keep in mind the differences between liquid and dry measurements and between Roman and English custom. dropsy is a now archaic term for swelling in body tissues due to accumulation of excess fluid. Its use in English comes through the French hydropsie, from the Greek hydrops, hydor being the Greek word for water. In former times, "dropsy" often was used as a diagnosis in itself. Now we refer to edema, ascites, or anasarca as more descriptive signs, and we require a designation of the underlying cause, such as congestive heart failure or cirrhosis, as the diagnosis. This refined perception accounts for the disuse of "dropsy." (see hydrops) drosophila is the proper name of the common fruit-fly, a ubiquitous denizen of biology laboratories and produce stands. Its full name is Drosophila melanogaster, literally "blackbellied dew-sipper" (Greek drosos, "dew," + philos, "affinity"; melanos, "black," + gaster, "belly"). 70 drug dystrophy drug is a word that etymologists either avoid or treat at undue length. The reason is that no one can be sure of its origin. The Middle English droge and the Old French drogue both referred to chemical substances variously used as medicaments or dyes. A related word is the Dutch droog, "dry," as applied to any dessicated substance, such as herbs, duct is a contraction ofthe Latin ductus, "a drawing or a leading," which is related, in turn, to the verb ductere, "to draw, to lead, orto escort." However, Latin authors never used ductus when they referred to a conduit for fluids. Rather, they used canalis, "a pipe or gutter.” duodenum began as the Greek dodeka-daktulon, "twelve fingers," the idea being thatthe most proximal portion of the small intestine from the pylorus to the ligament of Treitz is about twelve finger-breadths long. This came to be translated, through the Arabic, as the Late Latin duodenum. In classical Latin this would have been duodecim, "twelve" (from duo, "two," + decern, "ten"). In German, the duodenum is der Zwolffingerdarm, "the twelvefinger intestine." dura mater is the name for the tough, outer membrane encasing the brain and spinal cord. It is composed of the Latin words dura, "hard or tough," and mater, "mother." This makes little sense until one knows that the Latin dura mater is a literal translation of its precedent, the Arabic term which meant "strong mother" (in a sense suggesting 'protector') of the brain." The Arabs liked to use their word for "mother" as a figure ofspeech, dys- is an inseparable combining form, originating in the Greek, that confers a bad sense on whatever word to which it is attached. "Dys-" conveys a meaning of defective, difficult, ill, or painful. There are a host of medical terms beginning with "dys-." Some of them are closely related to Greek words. Some "dys-" words are more tortuously contrived. An example is dysfunction, to refer to anything that goes wrong. Incidentally, "dys-" is notto be confused with dis-, a prefix borrowed from the Latin and meaning "apart, asunder, deprived of." dyschezia (see -chezia) dyscrasia is an almost direct borrowing ofthe Greek dyskrasia, "a bad mixture of humors, a bad temperament"; the Greek krasis means "mixture or make-up." The term originally referred to any diseased condition but now, for some obscure reason, is restricted to hematology, as in "blood dyscrasias." dysentery is the condition of a painful gut, usually attended by diarrhea. To the Greeks dysenteria {dys- + enteron, "intestine") meant any sort of bowel complaint, dysgeusia combines dys- + Greek geusis, "taste"and is a pretentious way ofsaying "a bad taste in the mouth." dyskinesia is a direct borrowing of the Greek word for "difficulty of movement" {dys- + kinesis, "motion"). The term includes a variety of impairments in voluntary and involuntary muscular contractions, dyslexia joins dys- + Greek lexis, "diction" to designate an impaired ability to read or write words, a familial disorder more frequent in boys, (see alexia) dyspareunia is taken from the Greek dyspareunos, literally "ill-mated." The Greek pareunos {para-, "beside," + eunos, "bed") means "lying beside." Now the term is restricted to painful sexual intercourse. dyspeptic describes a nondescript digestive malaise. The term was contrived by combining dys- + Greek pepsis, "digestion." dysphagia means difficult or impaired swallowing {dys- + Greek phagein, "to swallow”). Aphagia is total inability to swallow, dyspnea relates to the Greek dyspnoia {dys- + pnoia, "breathing"), and both mean "difficult or labored breathing." To detect subtly labored breathing, try breathing in synchrony with your patient. You may be surprised how readily dyspnea thereby becomes evident, dystrophy is an abnormal growth or development, from whatever cause. The term combines dys- + Greek trophe, "nourishment."

• Kala-azar is the Hindi name for "black fever," so called by the people of the Assam province in northeast India where the disease is endemic. The common name was given because of the dusky hue ofthe skin assumed by victims in the later phase ofthe disease. The cause is infection by a protozoon now called Leishmania donovani, and the visceral form ofthe disease is known as leishmaniasis (the "ei" is pronounced "ee"). It was Sir William Leishman (1865-1926), ofHer Britannic Majesty's Indian Medical Service, who first discovered the parasite in a spleen at necropsy in 1900, a finding later confirmed by his colleague, Dr. Charles Donovan (1863-1951), an Irish physician in the Indian Sanitary Service. kallikrein was the name given by H. Kraut, E.K. Frey, and E. Werle (Hoppe Seyler's Z Physiol Chem. 1930,-189:97) to a hypotensive substance of which they found the pancreas to be a majorsource. The name is contrived from a Greek word for the pancreas. It is possible thatthe Greeks may have referred to the pancreas (which they usually called pa[n]gkreas) as kallikreas, this being a combination of kalli, "beautiful, delectable," + kreas, "a piece of meat." (see pancreas) kaolin is taken from a French version of the Mandarin Chinese kao-ling, "high hill," which describes the place where the clay-like silicate of aluminum was first found in an area of Jiangxi province. Originally, it was used by the Chinese in the manufacture of porcelain, then exported to Europe for the same purpose. Later, a pulverized form was utilized in the pharmacy as a coating for pills and then emulsified as a medicine itselfin the treatment ofdiarrhea because ofits adsorptive properties. karyo- is a combining form taken from the Greek karyon, "a nut," and used in reference to the nucleus of a cell. A karyocyte is a nucleated cell. Karyolysis is a degenerative process wherein the nucleus of a cell swells, then loses its chromatin (+ Greek lysis, “a dissolution"). keloid is usually attributed to the Greek kele, “a rupture, as a hernia," though it could also come from the Greek kelis, "a blemish" or the Greek chele, "a hoof, claw, or talon." Any or all of these could describe the tough, tumorlike scar that occurs after the healing ofskin wounds in certain susceptible persons. Such a scar was called "keloid" by Jean Louis Albert (1768-1837), a French dermatologist, in 1835. keratin is the name for the protein constituent ofskin, hair, nails, and horny excrescences. It is attributed to the Indo-European ker, "hom," which led to the Greek keros. The rhinoceros gets his name from the prominent horn on his nose. Keratosis is an abnormal horny excrescence ofthe skin orsquamous mucosa. kernicterus is a potentially dangerous form of jaundice observed in hemolytic disease ofthe newborn. Babies are unable to conjugate the burden of bilirubin catabolized from heme that is released by dissolution of red blood cells; the unconjugated bilirubin then spills over the blood-brain barrier and lodges destructively in various vital centers ofthe brain, including bulbar, cerebellar, and cerebral nuclei. The term is a hybrid of the German Kern, "kernel," or, in anatomy, "nuclei," + the Greek ikteros, "jaundice." ketones are organic compounds containing a carbonyl group (=C=0). The prototype is acetone (dimethyl ketone), so named from the Latin acetum, "vinegar," + the Greek -one, "a female descendent," in the sense of a weaker derivative. One might conclude that acetone was firstthoughtto be a "weak sister" of acetic acid. The German word for acetone is Aketon, and the generic term "ketone" emerged by simply dropping the initial "a" and adding a terminal "e.” kidney as a name for the paired, retroperitoneal organs of urinary excretion is hard to track down. In Middle English, says the Reverend Skeat, the spelling was variously kidneer, kidnere, or kidenei. The second syllable ofthe first two forms would seem to be related to a 126 kilo- kuru common Indo-European root from which the Greek nephros, the Old Icelandic nyra, and the German Mere are derived; all mean "kidney." Kidenei has been postulated as a combination of the Old English cyd, "pod or husk/' + [n]ei, "egg." Apparently there was confusion in ancient times as to whether the testis or the kidney was the source ofsperm. The Romans gave up and called the kidneys renes, from which we take our adjective renal. The Latin rigare means "to convey water." "Kidney" also has been used as a figure ofspeech to refer to a sort of temperament or nature. This is in keeping with the old proclivity to ascribe temperamental characteristics to certain organs of the body. Two fellows who take much the same view of things might be described as "men of the same kidney." The ancient Hebrews believed the kidneys were the seat of affections or passions. Solomon proclaimed, "Yea, my reins [kidneys] shall rejoice when thy lips speak right things” (Proverbs 23:16). kilo- is the prefix denoting one thousand or 103 of anything. It comes from the Greek khilioi, "a thousand." (see numbers) kindred in both lay language and in genetics means "a family relationship." "Kin" can be traced to the Old English cyrm, “one's own people or race," and is analogous to the Greek genos and the Latin genus. The sense is that of persons or things related by a common origin or stock. Similarly derived is our word "kind," with the meanings both "of similar type" and of "acting in a nice way." Thus, to be kindly is to treat one as a member ofthe family. Would that all members of a kindred always treated each other kindly! kine-, kinesio- are prefixes denoting movement and come from the Greek kinesis, "motion." Another derivative is “cinema," a highfalutin name for the movies. Kinesthesia is the sense by which movement of a part is perceived (kine- + Greek aisthesis, "feeling"), king's evil was a medieval term for scrofula or cervical lymphadenopathy, which probably in most cases was tuberculous adenitis. The original Late Latin term was morbus regius (also applied to jaundice, as previously noted), the reference being not to a king afflicted but rather to the belief that a "laying on" of the royal hand was a sure cure. England's Edward the Confessor, in the 11th century, was a foremost practitioner of the royal touch, and Charles II is said to have "laid hands" on a hundred thousand of his subjects, doubtless in an effort to bolster his shaky reign (1660-1685). The ancient practice of "laying on of hands" persists today. One of my wise professors of medicine advised, "Always put your hand where the patient says it hurts." kinins are so called, being derived from the Greek kinesis, "motion,” because they are endogenous peptides having an effect on the movement of Smooth Muscle. Bradykinins (Greek brady, "slow”) cause slow movement or contraction of gut muscle, knee originated in the Indo-European gneu or genu, the latter being taken directly into Latin and into Greek as gonu. In Old English this became cneow, from which "knee" eventually emerged. The names of geometric figures are suffixed by a derivative of the Greek gonu. A pentagon has five angles or "knees." kneecap (see patella) knock-kneed (see valgus) knuckle began as the Old English cnucl and is related to the Dutch knokkel, the diminutive of knok, "bone," hence a little bone. More specifically, "knuckle” bears a relation to “knee," implying a bend or angle, (see knee) koilo- is a combining form taken from the Greek koilos, "hollow or concave." A koilocyte is a hollow or empty cell, devoid of its normal cytoplasmic content. Koilonychia (+ Greek onyx, "nail") is a condition wherein the fingernails (and, in some cases, the toenails) assume a concave shape; it is sometimes called "spoon nail." kuru is a word used by the Fore people of the eastern highlands of Papua, New Guinea, to denote tremor. It has been applied as a name of an exotic neuropathy that has excited biomedical interest far beyond its endemic location in Melanesia. Kuru has been found to be due to a "slow virus," i.e., a virus that wreaks its havoc long after the initial infection. In the primitive culture of New Guinea, kuru was transmitted by the eating of infected brain tissue. Fortunately, since cannibalism has declined in that area, so has the incidence of kuru. (see scrapie) 127 kwashiorkor kyphosis kwashiorkor in the language of Ghana means "displaced or strange child"; it can also mean "red boy." It has been taken to name a syndrome of severe nutritional protein deficiency characterized by changes in pigmentation ofskin and hair, together with a pot-belly due to ascites. When there is an associated calorie deficiency, the syndrome includes a marked wasting of muscle and subcutaneous fat, a condition known as marasmic kwashiorkor, (see marasmus) kymograph was given in 1847 by Karl Friedrich Wilhelm Ludwig (1816-1895), an eminent German physiologist, as the name for an instrument on which moving or "wavy" lines could be recorded on a revolving drum. The name was contrived from the Greek kyma, "a wave,” + graphein, "to write." In early kymography, smoked paper was stretched around a rotating cylinder, etched with a fine needle, then preserved with a coat ofshellac. kyphosis comes from the Greek kyphos, "bent or bowed,” and usually refers to a bowing of the dorsal spine. It is a sign of osteoporosis affecting the thoracic vertebrae and is commonly seen in postmenopausal women. It Is sometimes referred to as a "dowager's hump."