|Medical Dictionary - Dictionary of Medicine and Human Biology|
A red blood cell of irregular shape. [poikilo- + G. kytos, cell]
SYN: poikilocytosis. [poikilocyte + G. haima, blood]
The presence of poikilocytes in the peripheral blood. SYN: poikilocythemia. [poikilocyte + G. -osis, condition]
Hypoplastic defects or mottling of enamel due to excessive fluoride in the water supply. [poikilo- + L. dens, tooth, + G. -osis, condition]
A variegated hyperpigmentation and telangiectasia of the skin, followed by atrophy. [poikilo- + G. derma, skin] p. atrophicans and cataract SYN: Rothmund syndrome. p. atrophicans vasculare a rare condition that simulates chronic radiodermatitis in appearance; may eventuate as mycosis fungoides. SYN: parapsoriasis lichenoides. p. of Civatte reticulated pigmentation and telangiectasia of the sides of the cheeks and neck; common in middle-aged women. p. congenitale SYN: Rothmund syndrome.
A poikilothermic animal. SYN: allotherm, cold-blooded animal.
poikilothermic, poikilothermal, poikilothermous (poy′ki-lo-ther′mic, -mal, -mus)
1. Varying in temperature according to the temperature of the surrounding medium; denoting the so-called cold-blooded animals, such as the reptiles and amphibians, and the plants. 2. Capable of existence and growth in media of varying temperatures. Cf.:heterothermic, homeothermic. 3. Causing a disruption of normal hypothalamic thermoregulatory function, as seen with drugs such as phenothiazines. SYN: cold-blooded, hematocryal. [poikilo- + G. therme, heat]
poikilothermy, poikilothermism (poy′ki-lo-ther′me, -therm′izm)
The condition of plants and cold-blooded animals, the temperature of which varies with the changes in the temperature of the surrounding medium. [poikilo- + G. therme, heat]
A blood platelet of abnormal shape. [poikilo- + G. thrombos, clot, + kytos, cell]
A rarely used term for a mental state marked by abnormal variations in mood. [poikilo- + G. thymos, mind]
1. SYN: punctum. 2. A sharp end or apex. 3. A slight projection. 4. A stage or condition reached, as the boiling p. 5. To become ready to open, said of an abscess or boil the wall of which is becoming thin and about to rupture. 6. In mathematics, a dimensionless geometric element. 7. A location or position on a graph, plot, or diagram. 8. Decimal p.. [Fr.; L. punctum, fr. pungo, pp. punctus, to pierce] p. A SYN: subspinale. absorbent points cones of paper or paper products used for drying or maintaining medicaments during root canal therapy. alveolar p. SYN: prosthion. anterior focal p. the p. where parallel rays from the retina are focused. apophysary p., apophysial p. 1. SYN: subnasal p.. 2. SYN: Trousseau p.. auricular p. SYN: auriculare. axial p. SYN: nodal p.. p. B SYN: supramentale. boiling p. (b.p.) the temperature at which the vapor pressure of a liquid equals the ambient atmospheric pressure. Cannon p. the location in the mid–transverse colon at which innervation by superior and inferior mesenteric plexuses overlaps at the junction of the primitive midgut and hindgut, frequently resulting in narrowing evident on barium enema. See Cannon ring. SYN: Cannon ring. Capuron points the iliopubic eminences and the sacroiliac joints, constituting four fixed p. in the pelvic inlet. cardinal points 1. the four points in the pelvic inlet toward one of which the occiput of the baby is usually directed in case of head presentation: two sacroiliac articulations and the two iliopectineal eminences corresponding to the acetabula; 2. six points of a compound optical system: the anterior focal p., the posterior focal p., the two principal points, and the two nodal points. central-bearing p. the contact p. of a central-bearing device. Clado p. a p. at the junction of the interspinous and right semilunar lines, at the lateral border of the rectus abdominis muscle, where marked tenderness on pressure is felt in some cases of appendicitis. clinical end p. traditional medical measures of a diagnostic or therapeutic impact that may or may not be perceived by the patient. cold-rigor p. the degree of lowered temperature at which the activity of a cell ceases and the cell passes into the narcotic or hibernating state. congruent points the p. in each retina referred to the same external stimulus. conjugate p. a p. so related to another that an object at one is imaged at the other. contact p. SYN: contact area. points of convergence convergence. craniometric points fixed points on the skull used as landmarks in craniometry. critical p. a p. at which two phases become identical; thus, at a given critical temperature and critical pressure, the liquid and gaseous state of a particular substance can no longer be differentiated. dew p. the temperature at and below which moisture will condense for a specific humidity. p. of elbow SYN: olecranon. end p. the completion of a reaction; usually evident by the first perceptible alteration of the color of an added indicator. equivalence p. SYN: equivalence zone. far p. that p. in conjugate focus with the retina when the eye is not accommodating. SYN: punctum remotum. p. of fixation the p. on the retina at which the rays coming from an object regarded directly are focused. SYN: p. of regard. flash p. the lowest temperature at which vapors of a liquid may be ignited by a flame. focal p. anterior focal p., posterior focal p.. freezing p. the temperature at which a liquid solidifies. fusing p. fusion temperature (wire method). Guéneau de Mussy p. a p., painful on pressure, at the junction of a line prolonging the left border of the sternum and a horizontal line at the level of end of the bony portion of the tenth rib; it is present in cases of diaphragmatic pleurisy. gutta-percha points cones of a gutta percha compound used for filling root canals in conjunction with a cement, paste, or plastic. Hallé p. a p. at the intersection of a horizontal line touching the anterior superior spine of the ilium and a perpendicular line drawn from the spine of the pubis; here the ureter can be most readily palpated. heat-rigor p. the degree of elevated temperature at which coagulation of protoplasm occurs with death of the cell. incident p. the p. at which a light ray enters an optical system. incisal p. the p. located between the incisal edges of the lower central incisors; the graphic projection of the excursions of the incisal p. in certain planes is generally used to illustrate the envelope of motion of mandibular movement. isoelectric p. (pI, IEP, I.P., i.p.) the pH at which an amphoteric substance, such as protein or an amino acid, is electrically neutral. isoionic p. the pH at which a zwitterion has an equal number of positive and negative charges; in water and in the absence of other solutes, this is the isoelectric p.. isosbestic p. in applied spectroscopy, a wavelength at which absorbance of two substances, one of which can be converted into the other, is the same. J p. the p. marking the end of the QRS complex and the beginning of the S or T wave in the electrocardiogram. SYN: ST junction. jugal p. SYN: jugale. lower alveolar p. SYN: infradentale. malar p. apex of the tuberosity of the zygomatic (malar) bone. p. of maximal impulse the p. on the chest wall at which the maximal cardiac impulse is seen and/or felt. maximum occipital p. the p. on the squama of the occipital bone farthest from the glabella. Mayo-Robson p. a p. just above and to the right of the umbilicus, where tenderness on pressure exists in disease of the pancreas. McBurney p. a p. between 112 and 2 inches superomedial to the anterior superior spine of the ilium, on a line joining that process and the umbilicus, where pressure elicits tenderness in acute appendicitis. median mandibular p. a p. on the anteroposterior center of the mandibular ridge in the median sagittal plane. melting p. (m.p., Tm) 1. the temperature at which a solid becomes a liquid; 2. the temperature at which 50% of a macromolecule becomes denatured. mental p. SYN: pogonion. metopic p. SYN: metopion. motor p. a p. on the skin overlying the endplates of an underlying muscle; the application of an electrical stimulus, via an electrode, will cause contraction of the muscle. Munro p. a p. at the right edge of the rectus abdominis muscle, between the umbilicus and the anterior superior spine of the ilium, where pressure elicits tenderness in appendicitis. nasal p. SYN: nasion. near p. that p. in conjugate focus with the retina when the eye exerts maximal accommodation. SYN: punctum proximum. neutral p. the p. at which a solution is neither acid nor alkaline (pH 7 at 22°C for aqueous solutions). nodal p. one of two points in a compound optical system so related that a ray directed toward the first p. will appear to have passed through the second p. parallel to its original direction. SYN: axial p.. occipital p. the most prominent posterior p. on the occipital bone above the inion. p. of ossification SYN: ossification center. painful p. Valleix points. posterior focal p. the p. of a compound optical system where parallel rays entering the system are focused. power p. in dentistry, the vertical dimension at which the greatest masticatory force may be registered. preauricular p. a p. of the posterior root of the zygomatic arch lying immediately in front of the upper end of the tragus. pressure p. a cutaneous locus having pressure-sensitive elements that, when compressed, yield a sensation of pressure. primary p. of ossification SYN: primary ossification center. principal p. one of two points on an optic axis so related that an object at one is exactly imaged at the other without magnification, minification, or inversion. p. of proximal contact SYN: contact area. p. of regard SYN: p. of fixation. retention p. a provision made within a cavity preparation of a tooth to hold in place the first pieces of gold when placing a direct gold restoration. secondary p. of ossification SYN: secondary ossification center. silver p. a solid core cone of silver used in filling root canals in conjunction with a cement or paste. spinal p. SYN: subnasal p.. subnasal p. the center of the root of the anterior nasal spine. SYN: apophysary p. (1) , apophysial p., spinal p.. Sudeck critical p. region in the colon between the supply of the sigmoid arteries and that of the superior rectal artery. supra-auricular p. a craniometric p. on the posterior root of the zygomatic process of the temporal bone directly above the auricular p.. supranasal p. SYN: ophryon. supraorbital p. SYN: ophryon. sylvian p. the nearest p. on the skull to the lateral (sylvian) fissure, about 30 mm behind the zygomatic process of the frontal bone. tender points SYN: Valleix points. trigger p. a specific p. or area where stimulation by touch, pain, or pressure induces a painful response. SYN: dolorogenic zone, trigger area, trigger zone. triple p. the temperature at which all three phases ( I.E., solid, liquid, and gas) are in equilibrium; the triple p. of water (273.16 K) is a fundamental fixed p. in temperature scales. Trousseau p. a painful p., in neuralgia, at the spinous process of the vertebra below which arises the offending nerve. SYN: apophysary p. (2) , apophysial p.. Valleix points various points in the course of a nerve, pressure upon which is painful in cases of neuralgia; these points are: 1) where the nerve emerges from the bony canal; 2) where it pierces a muscle or aponeurosis to reach the skin; 3) where a superficial nerve rests upon a resisting surface where compression is easily made; 4) where the nerve gives off one or more branches; and 5) where the nerve terminates in the skin. SYN: tender points. Weber p. a p. situated 1 cm below the promontory of the sacrum; believed by Weber to represent the center of gravity of the body. zygomaxillary p. SYN: zygomaxillare.
A massage manipulation with the tips of the fingers. [Fr. dotting, stippling]
Preparing to open spontaneously, said of an abscess or a boil.
In photometry, a very small source of light that is regarded as a geometric point from which light emanates in straight lines in all directions.
Paul J., French surgeon, 1853–1907. See P. gland, P. line.
poise (P) (poyz, pwahz)
In the CGS system, the unit of viscosity equal to 1 dyne-second per square centimeter and to 0.1 pascal-second. [J.-L. M. Poiseuille]
Jean Léonard Marie, French physiologist and physicist, 1799–1869. See poise, P. viscosity coefficient, P. law, P. space.
Any substance, either taken internally or applied externally, that is injurious to health or dangerous to life. [Fr., fr. L. potio, potion, draught] acrid p. a p. that causes a destructive local irritation as well as systemic effects. arrow p. 1. SYN: curare. 2. any natural toxin used for coating arrows, spears, and darts ( e.g., extracts containing aconitin, ouabain, cardiac glycosides, batrachotoxin, curare). fish p. 1. SYN: ichthyotoxicon. 2. SYN: fugu p.. fugu p. (foo′goo) a p. in the roe and other parts of various species of Diodon, Triodon, and Tetradon, fishes of eastern Asiatic waters. SYN: fish p. (2) . [Jap. fugu, a poisonous fish] respiratory p. SYN: respiratory inhibitor.
1. The administering of poison. 2. The state of being poisoned. SYN: intoxication (1) . ackee p. an acute and frequently fatal vomiting disease associated with central nervous system symptoms and marked hypoglycemia, caused by eating unripe ackee fruit of Blighia spaida, a tree common in Jamaica. SYN: Jamaican vomiting sickness. bacterial food p. a term commonly used to refer to conditions limited to enteritis or gastroenteritis (excluding the enteric fevers and the dysenteries) caused by bacterial multiplication per se or by a soluble bacterial exotoxin. blood p. See septicemia, pyemia. carbon disulfide p. acute or chronic intoxication by CS2, an industrial disease encountered among rubber workers and makers of artificial silk (rayon) by the viscose process; characterized by insomnia, listlessness, and irritability, followed by paralyses, impaired vision, peptic ulcer, and psychoses. carbon monoxide p. a potentially fatal acute or chronic intoxication caused by inhalation of carbon monoxide gas, which has an affinity 210 times that of oxygen for binding with hemoglobin (carboxyhemoglobinemia) and thus interferes with the transportation of oxygen and carbon dioxide by the blood. crotalaria p. p. of humans and animals with alkaloids of the plants Senecio (ragwort), Crotalaria (rattlebox), and Heliotropum; produces a veno-occlusive disease of the liver similar to Chiari disease. SYN: crotalism. cyanide p. a fairly common disease of herbivorous animals, caused by eating cyanogenic plants containing glucosides that are hydrolyzed, yielding hydrocyanic acid; some farm chemicals, such as fungicides or insecticides, may be causes of cyanide p.; hydrogen cyanide and its salts are extremely poisonous to humans, either by inhalation or by ingestion. Datura p. p. resulting from ingestion of plants of the genus Datura; symptoms are parasympatholytic in nature and in severe p. include central nervous system depression, circulatory failure, and respiratory depression. djenkol p. p. believed to result from eating excessive amounts of a bean, Pitecolobium lobatum; symptoms are pain in the renal region, dysuria, and later anuria; the djenkol bean has a high vitamin B content and is used for food despite its toxic qualities. ergot p. a syndrome brought on by the consumption of bread (notably rye) contaminated by the ergot fungus, Claviceps purpurea (rye smut), the source of numerous ergot alkaloids. The effects observed include peripheral vascular constriction leading to gangrene, partial paralysis with numbing, tingling, and burning in the limbs, feeble pulse, restlessness, stupor, or delirium; can prove fatal. food p. p. in which the active agent is contained in ingested food. lead p. acute or chronic intoxication by lead or any of its salts; symptoms of acute lead p. usually are those of acute gastroenteritis in adults or encephalopathy in children; chronic lead p. is manifested chiefly by anemia, constipation, colicky abdominal pain, neuropathy with paralysis with wrist-drop involving the extensor muscles of the forearm, bluish lead line of the gums, and interstitial nephritis; saturnine gout, convulsions, and coma may occur. SYN: plumbism, saturnism. mercury p. a disease usually caused by the ingestion or inhalation of mercury or mercury compounds, which are toxic in relation to their ability to produce mercuric ions; usually acute mercury p. is associated with ulcerations of the mouth (including loosening of teeth), stomach, and intestine and toxic changes in the renal tubules; anuria and anemia may occur; respiratory distress and pneumonia can follow inhalation; usually chronic mercury p. is a result of industrial p. and causes gastrointestinal or central nervous system manifestations including stomatitis, diarrhea, headaches, ataxia, tremor, hyperreflexia, sensorineural impairment, and emotional instability and sometimes delirium (Mad Hatter syndrome). SYN: hydrargyria, hydrargyrism, mercurialism. mushroom p. mycetism. oxygen p. SYN: oxygen toxicity. radiation p. SYN: radiation sickness. Salmonella food p. gastroenteritis caused by various strains of Salmonella that multiply freely in the gastrointestinal tract but do not produce septicemia; symptoms usually begin within 8–24 hours and include fever, headache, nausea, vomiting, diarrhea, and abdominal pain. scombroid p. p. from ingestion of heat-stable toxins produced by bacterial action on inadequately preserved dark-meat fish of the order Scombroidea (tuna, bonito, mackerel, albacore, skipjack); characterized by epigastric pain, nausea and vomiting, headache, thirst, difficulty in swallowing, and urticaria. silver p. SYN: argyria. Staphylococcus food p. outbreaks commonly caused by staphylococcal enterotoxin and characterized by an abrupt onset of gastroenteritis within several hours after ingestion of the food contaminated with the preformed exotoxin; vomiting is usually more severe and diarrhea less severe than in infectious forms of bacterial food p.. systemic p. SYN: toxicosis. tetraethyl p. tetraethyllead. thallium p. a condition characterized by vomiting, diarrhea, leg pains, and severe sensorimotor polyneuropathy; about 3 weeks after p., temporary extensive loss of hair typically occurs; usually occurs after accidental ingestion of a rodenticide. turpentine p. p. from oil of turpentine; symptoms include hematuria, albuminuria, and coma; the urine may have an odor of violets. SYN: terebinthinism.
poison ivy, poison oak, poison sumac
1. See Toxicodendron. 2. Common name for the cutaneous eruption (rhus dermatitis) caused by contact with these species of Toxicodendron.
Characterized by, having the characteristics of, or containing a poison. SYN: toxic (1) , toxicant (1) , toxiferous, venenous.
Siméon Denis, French mathematician, 1781–1840. See P. distribution, P.-Pearson formula.
1. Relating to a pole. 2. Having poles, said of certain nerve cells having one or more processes. [Mod. L. polaris, fr. polus, pole]
An instrument for measuring the angle of rotation in polarization or the amount of polarized light. [Mod. L. polaris, polar, + G. metron, measure]
Measurement by polarimeter.
An instrument for studying the phenomena of the polarization of light. [Mod. L. polaris, polar, + G. skopeo, to examine]
Relating to the polariscope or to polariscopy.
Use of the polariscope in studying properties of polarized light.
1. The property of having two opposite poles, as that possessed by a magnet. 2. The possession of opposite properties or characteristics. 3. The direction or orientation of positivity relative to negativity. 4. The direction along a polynucleotide chain, or any biopolymer or macrostructure ( e.g., microtubules). 5. With respect to solvents, ionizing power. 6. The tendency of an organism to develop differentially along an axis. [Mod. L. polaris, polar]
1. In electricity, coating of an electrode with a thick layer of hydrogen bubbles, with the result that the flow of current is weakened or arrested. 2. A change effected in a ray of light passing through certain media, whereby the transverse vibrations occur in one plane only, instead of in all planes as in an ordinary light ray. 3. Development of differences in potential between two points in living tissues, as between the inside and outside of a cell wall.
To put into a state of polarization.
The first element of a polariscope that polarizes the light, as distinguished from the analyzer, the second polarizing element.
That branch of electrochemistry concerned with the variation in current flowing through a solution as the voltage is varied; this will vary with the ionic concentration of reducible substances so that p. can be used in chemical analysis. P. is commonly employed in the form of a reduction at a dropping mercury electrode. [Mod. L. polaris, polar, + G. grapho, to write]
poldine methylsulfate (pol′den)
An anticholinergic agent.
pole (pol) [TA]
1. One of the two points at the extremities of the axis of any organ or body. 2. Either of the two points on a sphere at the greatest distance from the equator. 3. One of the two points in a magnet or an electric battery or cell having extremes of opposite properties; the negative p. is a cathode, the positive p. an anode. 4. Either end of a spindle. 5. Either of the differentiated zones at opposite ends of an axis in a cell, organ, or organism. SYN: polus [TA] . [L. polus, the end of an axis, p., fr. G. polos] abapical p. in an ovum, the p. opposite the animal p. ( i.e., vegetal p.). animal p. the point in a telolecithal egg opposite the yolk, where most of the protoplasm is concentrated and where the nucleus is located; from this region, the polar bodies are extruded during maturation. SYN: germinal p.. anterior p. of eyeball [TA] the center of the corneal curvature of the eye. SYN: polus anterior bulbi oculi [TA] . anterior p. of lens [TA] the central point on the anterior surface of the lens of the eye. SYN: polus anterior lentis [TA] . cephalic p. the head end of the fetus. frontal p. [TA] SYN: frontal p. [TA] of cerebrum. frontal p. [TA] of cerebrum the most anterior promontory of each cerebral hemisphere. SYN: frontal p. [TA] , polus frontalis [TA] . germinal p. SYN: animal p.. inferior p. [TA] for a structure having a vertically oriented long axis, the point at the lower end of the axis, nearest the soles of the feet; the lowest point of a structure's surface. See inferior p. of kidney, lower p. of testis. SYN: extremitas inferior [TA] , lower p. [TA] , inferior extremity (1) &star, polus inferior&star. inferior p. of kidney [TA] the inferior end of the kidney. SYN: extremitas inferior renis [TA] , inferior extremity of kidney&star, polus inferior renis&star. inferior p. of testis lower p. of testis. lateral p. SYN: tubal extremity of ovary. lower p. [TA] SYN: inferior p.. lower p. of testis [TA] the inferior end of the testis. SYN: extremitas inferior testis [TA] , inferior p. of testis&star, polus inferior testis&star. medial p. of ovary SYN: uterine extremity of ovary. occipital p. [TA] SYN: occipital p. [TA] of cerebrum. occipital p. [TA] of cerebrum the most posterior promontory of each cerebral hemisphere; the apex of the occipital lobe. SYN: occipital p. [TA] , polus occipitalis [TA] . pelvic p. the breech end of the fetus. posterior p. of eyeball [TA] the center of the posterior curvature of the eye. SYN: polus posterior bulbi oculi [TA] . posterior p. of lens [TA] the central point on the posterior surface of the lens. SYN: polus posterior lentis [TA] . superior p. [TA] for a structure having a vertically oriented long axis, the point at the upper end of the axis, furthest from the soles of the feet; the highest point of a structure's surface. See superior p. of kidney, upper p. of testis. SYN: extremitas superior [TA] , upper p. [TA] , polus superior&star, superior extremity (1) &star. superior p. of kidney [TA] the superior end of the kidney. SYN: extremitas superior renis [TA] , polus superior renis&star, superior extremity of kidney&star. superior p. of testis upper p. of testis. temporal p. [TA] SYN: temporal p. [TA] of cerebrum. temporal p. [TA] of cerebrum the most prominent part of the anterior extremity of the temporal lobe of each cerebral hemisphere, a short distance below the fissure of Sylvius. SYN: polus temporalis [TA] , temporal p. [TA] . upper p. [TA] SYN: superior p.. upper p. of testis [TA] the superior end of the testis. SYN: extremitas superior testis [TA] , polus superior testis&star, superior p. of testis&star. vegetal p., vegetative p. the part of a telolecithal egg where the bulk of the yolk is situated. vitelline p. the vegetative p. of an ovum.
See under number.
An instrument, usually a rubber-tipped rod, for removing solid particles from a container, particularly the walls of that container.
Abbreviated term for poliomyelitis.
Gray; gray matter (substantia grisea). [G. polios]
Destructive to gray matter of the nervous system. [polio- + G. klastos, broken]
SYN: poliodystrophy. p. cerebri progressiva infantilis [MIM*203700] autosomal recessively inherited progressive spastic paresis of extremities with progressive mental deterioration, with development of seizures, blindness, and deafness, beginning during the first year of life, and with destruction and disorganization of nerve cells of the cerebral cortex. SYN: Alpers disease, Christensen-Krabbe disease, progressive cerebral poliodystrophy.
Wasting of the gray matter of the nervous system. SYN: poliodystrophia. [polio- + G. dys-, bad, + trophe, nourishment] progressive cerebral p. SYN: poliodystrophia cerebri progressiva infantilis.
Inflammation of the gray matter of the brain, either of the cortex or of the central nuclei; as contrasted to inflammation of the white matter. [polio- + G. enkephalos, brain, + -tis, inflammation] p. infectiva SYN: von Economo disease. inferior p. p. with predominantly bulbar paralysis. superior p. p. with ophthalmoplegia. superior hemorrhagic p. SYN: Wernicke syndrome.
Inflammation of the gray matter of the brain and spinal cord and of the meningeal covering of the parts. [polio- + G. enkephalos, brain, + meninx, membrane, + myelon, marrow, + -itis, inflammation]
Inflammation of the gray matter of the brain and spinal cord.
Any disease of the gray matter of the brain. [polio- + G. enkephalos, brain, + pathos, suffering]
An inflammatory process involving the gray matter of the cord. [polio- + G. myelos, marrow, + -itis, inflammation] acute anterior p. a disease that results in death or irreversible damage of motor cells in the cerebrum, brainstem, and spinal cord, caused by infection with small RNA enteroviruses of the Picornaviridae group; formerly due almost solely to one of three types of polio virus, but now more often caused by coxsackieviruses A and B, or echoviruses. acute bulbar p. p. virus infection affecting nerve cells in the medulla oblongata and producing paralysis of the lower motor cranial nerves. chronic anterior p. muscular atrophy of the upper extremities and neck, in which there are long intermissions of quiescence or improvement; not to be confused with p. virus infections.
Acute anterior poliomyelitis with pronounced cerebral signs. [polio- + G. myelon, marrow, + enkephalos, brain, + -itis, inflammation]
Any disease of the gray matter of the spinal cord. [polio- + G. myelon, marrow, + pathos, suffering]
A patchy absence or lessening of melanin in hair of the scalp, brows, or lashes, due to lack of pigment in the epidermis; it occurs in several hereditary syndromes but may be caused by inflammation, irradiation, or infection such as herpes zoster. SYN: trichopoliosis. [G., fr. polios, gray] ciliary p. SYN: piebald eyelash.
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