A mineral of pitchlike appearance, chiefly uranium dioxide, the main source of uranium and elements, such as radium, produced as a result of the radioactive breakdown of that ...
1. The center of a hair. 2. The spinal cord and medulla oblongata. 3. To pierce the medulla of an animal with a sharp instrument introduced at the base of the skull. [A.S. ...
Resembling an ape. [G. pithekos, ape, + eidos, resemblance]
The nuclear spindle in karyokinesis. [G. pithodes, like a jar, fr. pithos, earthenware wine-jar, + eidos, resemblance]
Henri, French engineer, 1695–1771. See P. tube.
Jean A., French physician, 1848–1927. See P. area, P. sign.
In dentistry, the formation of well defined, relatively deep depressions in a surface, usually used in describing defects in surfaces (often golds, solder joints, or amalgam). ...
The primary cell of the posterior lobe of the pituitary gland, a fusiform cell closely related to neuroglia. [pituitary + G. kytos, cell]
A rare gliogenous neoplasm derived from pituicytes, occurring in the posterior lobe of the pituitary gland and characterized by cells with relatively small, round or oval nuclei ...
A thick nasal secretion. SYN: glairy mucus. [L. phlegm or thick mucous secretion]
Pituitary dysfunction. See hyperpituitarism, hypopituitarism.
Relating to the p. gland (hypophysis). SYN: pituitarium. [L. pituita, a phlegm]
- anterior p. the dried, partially defatted, and powdered anterior lobe of the p. gland of cattle, ...
A benign tumor of the pituitary, the master gland that controls other glands and influences numerous body functions including growth.
Dwarfism caused by a lack of growth hormone, usually due to malfunction of the pituitary gland. Children with growth hormone deficiency may grow normally for the first two to ...
Excessive growth and too much height due to chronic overactivity of the pituitary gland which is located at the base of the brain. (Growth hormone is specifically made by the ...
The main endocrine gland. It is a small structure in the head. It is called the master gland because it produces hormones that control other glands and many body functions ...
The front portion of the pituitary, a small gland in the head called the master gland. Hormones secreted by the anterior pituitary influence growth, sexual development, skin ...
The back portion of the pituitary, a small gland in the head called the master gland. The posterior pituitary secretes the hormone oxytocin which increases uterine contractions ...
A dermatosis marked by branny desquamation. [G. fr. pityron, bran, dandruff]
- p. alba patchy hypopigmentation of the skin resulting from mild dermatitis.
- p. alba ...
A mild form of eczema that occurs in young children and adolescents and produces mild patchy lightening and slight scaling of the skin of the face (particularly over the cheeks ...
pityriasis lichenoides chronica
An eruption, lasting up to a few years, of reddish-brown papules with central scaling; it clears without scarring. [lichenoides Mod. L., fr. G. leichen, lichen, a lichen-like ...
SYN: furfuraceous. [G. pityrodes, branlike, fr. pityron, bran, + eidos, resemblance]
A genus of fungi of disputed pathogenicity found in dandruff and seborrheic dermatitis. [G. pityron, bran, + sporos, seed]
- P. orbiculare SYN: Malassezia furfur.
- P. ovale ...
USAN-approved contraction for trimethylacetate, (CH3)3C–CO2−.
A post upon which something hinges or turns.
- adjustable occlusal p. an occlusal p. that may be adjusted vertically by means of a screw or by other means.
- occlusal p. an ...
A contraction for picture element, a two-dimensional representation of a volume element ( voxel) in the display of the CT or MR image, usually 512 × 512 or 256 × 256 pixels, ...
Abbreviation for pyruvate kinase.
The negative decadic logarithm of the ionization constant (Ka) of an acid; equal to the pH value at which equal concentrations of the acid and conjugate base forms of a ...
Abbreviation for picokatal.
Abbreviation for phenylketonuria.
Abbreviation for peak kilovoltage, the nominal voltage setting of an x-ray machine.
Abbreviation for placental lactogen.
A "sugar pill" or any dummy medication or treatment. For example, in a controlled clinical trial, one group may be given a real medication while another group is given a ...
A positive medical response to taking a placebo, as if it were an active medication. Up to one-third of patients given a placebo may respond with a reduction in symptoms, ...
A temporary organ joining the mother and fetus, the placenta transfers oxygen and nutrients from the mother to the fetus, and permits the release of carbon dioxide and waste ...
A placenta that invades the uterine wall. In placenta percreta, the vascular processes of the chorion (the chorionic villi), a fetal membrane that enters into the formation of ...
A placenta implanted near the outlet of the uterus, so that at the time of delivery the placenta precedes the baby. Placenta praevia can cause painless bleeding in the last third ...
An extra placenta separate from the main placenta. Also called a succenturiate or supernumerary placenta. Placenta accreta: The abnormal adherence of the chorionic villi to ...
Location of the placenta in the lower part of the uterus (womb) so that the placenta partially or completely covers the cervix. Also known as a placenta previa.
An extra placenta separate from the main placenta. In anatomy "succenturiate" means accessory to an organ. In this case, a succenturiate placenta is an accessory ...
Plural of planum. [L.]
A small, flat plate or dish used to support a sample for radioactivity determination; the sample is usually evaporated on (in) the p.. [Fr. planchette, dim. of planche, plank]
Max, German physicist and Nobel laureate, 1858–1947. See P. constant, P. theory.
1. A two-dimensional flat surface. See planum. 2. An imaginary surface formed by extension of a point through any axis or two definite points, in reference especially to ...
SYN: tomography. [L. planum, plane, + G. graphe, a writing]
An instrument formed of jointed levers with a recording index, used for measuring the area of any surface, by tracing its boundaries. [L. planum, plane, + G. metron, measure]
The measurement of surface areas and perimeters by tracing the boundaries. P. on photomicrographs or projected images may be used to evaluate the size of cells.
A diagram of the chest showing the front and back in plane projection, after the manner of Mercator projection of the earth's surface.
A general term for many floating marine forms, mostly of microscopic or minute size, which are moved passively by winds, waves, tides, or currents; it includes diatoms, algae, ...
plano-, plan-, plani-
1. A plane; flat, level. [L. planum, plane; planus, flat] 2. Wandering. [G. planos, roaming]
Relating to or composed of flat cells. [L. planus, flat, + cellular]
Flat on one side and concave on the other; denoting a lens of that shape.
Flat on one side and convex on the other; denoting a lens of that shape.
A rarely used term for the morbid impulse to leave home and discard social restraints. [G. planos, wandering, + mania, frenzy]
A European and North African genus of freshwater snails (family Planorbidae), including P. p., intermediate host of the sheep and cattle fluke, Paramphistoma cervi. [G. planos, ...
A condition in which the longitudinal arch of the foot is flattened and the hindfoot is everted. [plano- + L. valgus, turned outward]
SYN: sole. [L.]
- p. pedis [TA] SYN: sole of foot.
The root and leaves of the common or large-leaved plantain, P. major (family Plantaginaceae). [L. plantain]
- p. ovata coating the separated outer mucilaginous layers of P. ...
Pain on the plantar surface of the foot over the plantar fascia. [L. planta, sole of foot, + G. algos, pain]
Having to do with the sole of the foot. The plantar response (also known as the Babinski reflex) is elicited by stroking the sole. The plantar fascia is the ...
The plantar response, also known as the Babinski response, is an important neurologic examination based upon what the toes do when the sole (the plantar surface) of the foot is ...
Warts that grow on the soles of the feet. Plantar warts are different from most other warts. They tend to be flat and cause the buildup of callus (that has to be peeled away ...
Walking with the entire sole and heel of the foot on the ground, as do humans and bears. [L. planta, sole, + gradior, to walk]
Name given by Lankester to a coelenterate embryo when it consists of the two primary germ layers only, the ectoderm and endoderm. [L. dim. of planum, flat surface]
SYN: plane. [L. plane]
- plana coronalia SYN: frontal plane.
- plana frontalia [TA] SYN: frontal plane.
- horizontal planes [TA] plane parallel and relative to the horizon; in ...
1. Extravasation of urine. 2. The voiding of urine from an abnormal opening. [G. planos, wandering, + ouron, urine]
(1) An semi-hardened accumulation of substances from fluids that bathe an area. Examples include dental plaque and cholesterol plaque. Minerals form dental plaque around the teeth ...
An index for estimating the status of oral hygiene by measuring dental plaque that occurs in the areas adjacent to the gingival margin.
The most common form of psoriasis — about 80% of people with psoriasis have this type. Plaque psoriasis can appear on any skin surface, although the knees, elbows, scalp, ...
A plaque is a broad, raised area on the skin. Because it is raised, it can be felt (palpated). By definition, a skin plaque has a greater surface than its elevation above the ...
: The liquid part of the blood and lymphatic fluid, which makes up about half of its volume. Plasma is devoid of cells and, unlike serum, has not clotted. Blood plasma contains ...
plasma cell dyscrasia
A diverse group of diseases characterized by the proliferation of a single clone of cells producing a monoclonal immunoglobulin or immunoglobulin fragment (a serum M ...
The donation of sale of blood plasma for use in medical or other products. Unlike blood donors, most plasma “donors” in the US are paid. The procedure is done in a walk-in ...
Precursor of the plasma cell. SYN: plasmacytoblast. [plasma + G. blastos, germ]
A measure of the percentage of the volume of blood occupied by plasma, in contrast to a hematocrit. [plasma + G. krino, to separate]
A discrete, presumably solitary mass of neoplastic plasma cells in bone or in one of various extramedullary sites; in humans, such lesions are probably the initial phase of ...
1. Presence of plasma cells in the circulating blood. 2. Presence of unusually large proportions of plasma cells in the tissues or exudates. [ plasmacyte + G. -osis, condition]
A determinant of an inherited character located in the cytoplasm. SYN: cytogene. [plasma + gene]
A group of highly active oligopeptides found in sera that act upon smooth muscle of blood vessel s, uterus, bronchi, etc.; E.G., bradykinin, kallidin.
SYN: cell membrane. [plasma + G. lemma, husk]
Generic term for glycerophospholipids in which the glycerol moiety bears a 1-alkenyl ether group (on rarer occasions, a 1-alkyl ether group); e.g., ...
Long-chain aldehydes occurring in plasmalogens; e.g., stearaldehyde, palmitaldehyde.
Removal of whole blood from the body, separation of its cellular elements by centrifugation, and reinfusion of them suspended in saline or some other plasma substitute, thus ...
Proposed name for phosphatidates such as 2-acyl-1-alk-1-enylglycerol 3-phosphate.
A self-replicating (autonomous) circle of DNA distinct from the chromosomal genome of bacteria. A plasmid contains genes normally not essential for cell growth or survival. Some ...
A serine proteinase hydrolyzing peptides and esters of l-arginine and l-lysine and converting fibrin to soluble products; occurs in plasma as the precursor plasminogen ( ...
A precursor of plasmin. There is an autosomal dominant deficiency of p. [MIM*173350] that may promote thrombosis. See plasmin.
Term proposed for activator agents that produce plasmin by direct action on plasminogen; e.g., staphylokinase, plasminogen activator.
1. Relating to a plasmodium. 2. Relating to any species of the genus Plasmodium.
SYN: syncytiotrophoblast. [ plasmodium + G. trophe, nourishment, + blastos, germ]
The parasite guilty in the case of malaria (paludism). Plasmodium is a type of protozoa, a single-celled organism able to divide only within a host cell.
* * *
A genus of the ...
A former taxonomic category that included ameboid and flagellate Protozoa in which the nucleus is not separated into reproductive (micro-) and vegetative (macro-) portions; ...
Union of two or more cells with preservation of the individual nuclei; formation of a plasmodium. SYN: plasmatogamy, plastogamy. [ plasmo- + G. gamos, marriage]
SYN: protoplasm. [ plasmo- + G. -gen, producing]
Shrinking of plant cells by osmotic loss of cytoplasmic water. SYN: protoplasmolysis. [ plasmo- + G. lysis, dissolution]
The total of the extrachromosomal genetic determinants of the eukaryotic cell cytoplasm. SYN: plasmotype. [cytoplasm + -on]
The splitting open of a cell from the pressure of the protoplasm.
The splitting of protoplasm into fragments. [ plasmo- + G. schisis, a cleaving]
A highly viscous substance in cytoplasm containing discrete fibers of considerable length; a nucleoprotein regarded as the structural foundation of the cell.
A form of mitosis in multinuclear protozoan cells in which the cytoplasm divides into two or more masses, later reproducing, in some cases by sporulation. [ plasmo- + G. tome, ...
A condition in which the bone marrow, spleen, and liver are sites for the destruction of the erythrocytes, as opposed to destruction in the circulating blood. [ plasmo- + G. ...
Obsolete term for prothrombin. [ plasmo- + G. zyme, leaven]
1. Insoluble polypeptide formed through the random condensation of amino acid s or peptides under the catalytic influence of a proteinase-like chymotrypsin; molecular weights ...
1. A solid preparation that can be spread when heated and that becomes adhesive at the temperature of the body; used to keep the edges of a wound in apposition, to protect raw ...
1. Capable of being formed or molded. 2. A material that can be shaped by pressure or heat to the form of a cavity or mold. [G. plastikos, relating to molding]
- Bingham p. a ...
: A surgeon who specializes in reducing scarring or disfigurement that may occur as a result of accidents, birth defects, or treatment for diseases, such as melanoma. Many ...
: The field of surgery concerned with reducing scarring or disfigurement that may occur as a result of accidents, birth defects, or treatment for diseases, such as melanoma. ...
The capability of being formed or molded; the quality of being plastic.
1. One of the differentiated structures in cytoplasm of plant cells where photosynthesis or other cellular processes are carried on; plasid contain DNA and are ...
The chromenol ( isomeric) form of plastoquinone-9. SYN: solanochromene.
2,3-Dimethyl-1,4-benzoquinone with a multiprenyl side chain; a trivial name sometimes used for p.-9.
plastoquinone-9 (PQ-9), plastoquinone E9
2,3-Dimethyl-6-nonaprenyl-1,4-benzoquinone; one of a group of vitamins E and K and coenzymes Q; the isomeric form is plastochromenol-8; a participant in photosynthetic electron ...
The sternum with costal cartilages attached. [Fr. a breastplate]
1. [TA] In anatomy, a thin, relative flat, structure. SYN: lamina [TA]. 2. A metal bar perforated for screws applied to a fractured bone to maintain the ends in apposition. 3. ...
Joseph Antoine Ferdinand, Belgian physicist, 1801–1883. See P.- Talbot law.
A flat elevated segment of a graphic record. [Fr.]
- ventricular p. a level diastolic portion of the intraventricular blood pressure curve, representing graphically an ...
An irregular, disc-shaped element in the blood that assists in blood clotting. During normal blood clotting, the platelets clump together (aggregate). Although platelets are ...
Removal of blood from a donor with replacement of all blood components except platelets. [platelet + G. aphairesis, a withdrawal]
1. Sowing of bacteria on a solid medium in a Petri dish or similar container; the making of a plate culture. 2. Application of a metal bar to keep the ends of a fractured bone ...
Relating to platinum; denoting a compound containing platinum in its higher valency.
Relating to platinum; denoting a compound containing platinum in its lower valency.
A metallic element, atomic no. 78, atomic wt. 195.08, used for making small parts for chemical apparatus because of its resistance to acids; in powdered form (p. black), it is an ...
Pure platinum rolled into extremely thin sheets; its high fusing point makes it suitable as a matrix for various soldering procedures in dentistry and also suitable for ...
A group of six amphoteric elements: iridium, osmium, palladium, platinum, rhodium, and ruthenium.
Sir Harry, British surgeon, *1886. See Putti-P. operation, Putti-P. procedure.
Width; flatness. [G. platys, flat, broad]
A developmental anomaly of the skull or an acquired softening of the skull bones so that the floor of the posterior cranial fossa bulges upward in the region about the foramen ...
Flatness of the skull, a condition in which the vertical cranial index is below 70. SYN: platycrania. [ platy- + G. kephale, head]
A condition in which the tibia is abnormally broad and flat. SYN: platycnemism. [ platy- + G. kneme, leg]
SYN: platycephaly. [ platy- + G. kranion, skull]
Obsolete term for a relatively small giant cell sometimes formed in tubercles. [ platy- + G. kytos, cell]
Having a broad, flattened tongue. [ platy- + G. glossa, tongue]
Common name for any flatworm of the phylum Platyhelminthes; any cestode (tapeworm) or trematode (fluke). [ platy- + G. helmins, worm]
A phylum of flatworms that are bilaterally symmetric, flattened, and acelomate. There is no digestive tract in some platyhelminths (Cestoda), or the gut may be incomplete (without ...
Having a broad sacrum. [ platy- + G. heiron, sacrum]
Having a broad femur. [ platy- + G. meros, thigh]
Having a flat shape; term denoting an eye with a short anteroposterior axis. [ platy- + G. morphe, shape]
Broadness of the face; denoting a condition in which the orbitonasal index is less than 107.5. [ platy- + G. ops, eye, face]
Relating to or characterized by platyopia.
Having a broad pelvis, with an index below 90°. See p. pelvis. SYN: platypelloid. [ platy- + G. pellis, bowl (pelvis)]
Difficulty in breathing when erect, relieved by recumbency. Cf.:orthopnea. [ platy- + G. pnoe, a breathing]
1. Characterized by a nose of large width in proportion to its length. 2. Denoting a skull with a nasal index between 53 and 58. [ platy- + G. rhis, nose]
A condition in which the nose is wide in proportion to its length.
SYN: p. (muscle). [G. p., a flatplate]
Extreme width of the skull in the occipital region, with narrowing anteriorly and prognathism. [G. platystos, widest, superl. of platys, wide, + enkephale, brain]
Max A., U.S. dentist, 1903–1965. See P. curve.
A bacterial rod-shaped cell that contains a spore at one end, imparting a drumstick shape to the cell, such as the spore-containing cells in the organism causing tetanus, ...
A tuft of wool, cotton, or lint.
Rarely used alternative spelling for pleo-.
Multiple effects from a single gene. For example, the Marfan gene is pleiotropic with widespread effects and can cause long fingers and toes (arachnodactyly), dislocation of the ...
Production by a single mutant gene of apparently unrelated multiple effects at the clinical or phenotypic level. [ pleio- + G. tropos, turning]
- functional p. the p. due to the ...
A genus of microsporidians in the protozoan phylum Microspora, commonly found in fish and insects, with mononucleate, thick-walled spores in clusters of more than eight. An ...
SYN: pleochromatic. [ pleo- + G. chroa, color]
Property of showing changes of color when illuminated along different axes, as certain crystals or liquids. SYN: pleochroism. [ pleo- + G. chroma, color]
Presence of more cells than normal, often denoting leukocytosis and especially lymphocytosis or round cell infiltration; orginally applied to the lymphocytosis of the ...
Many-formed. A tumor may be pleomorphic. Pleomorphic is synonymous with protean (capable of assuming different shapes like the many-formed Greek god Proteus).
* * *
1. SYN: ...
An excess in the number of parts or in the size of a growth. Pleonasm comes from a Greek word (pleonasmos) meaning exaggeration or redundancy. A pleonasm in language is also a ...
Superabundance of bone formation. [ pleo- + G. osteon, bone, + -osis, condition]
- Leri p. SYN: dyschondrosteosis.
A term introduced by Bangerter to include all forms of treatment for amblyopia, particularly that associated with eccentric fixation. [ pleo- + optics]
An instrument for the treatment of amblyopia. [ pleo- + G. optos, visible, + phoros, bearing]
A stage in the development of a tapeworm following the procercoid stage, which develops in an animal serving as the second or subsequent intermediate host; a wormlike ...
Nearness, similarity. [G. plesios, close, near]
A genus of Gram-negative, facultatively anaerobic, chemoorganotropic, rod-shaped, motile bacteria. It possesses the enterobacterial common antigen. This genus is found in fish and ...
SYN: palpatory percussion. [G. plesso, to strike, + aisthesis, sensation]
An oblong flexible plate used in mediate percussion by being placed against the surface and struck with the plessor. SYN: pleximeter, plexometer. [G. plesso, to strike, + ...
A small hammer, usually with soft rubber head, used to tap the part directly, or with a plessimeter, in percussion of the chest or other part. SYN: percussor, plexor. [G. ...
1. SYN: hypervolemia. 2. An excess of any of the body fluids. [G. plethore, fullness, fr. pletho, to become full]
Relating to plethora. SYN: sanguine (1), sanguineous (2).
A device for measuring and recording changes in volume of a part, organ, or whole body. [G. plethysmos, increase, + grapho, to write]
- body p. a chamber apparatus surrounding the ...
Measuring and recording changes in volume of an organ or other part of the body by a plethysmograph. [G. plethysmos, increase, + graphe, a writing]
- impedance p. recording ...
Measuring the fullness of a hollow organ or vessel, as of the pulse. [G. plethysmos, increase, + metron, measure]
: The thin covering that protects and cushions the lungs. The pleura is made up of two layers of tissue that are separated by a small amount of fluid.
* * *
The serous membrane ...
Sounds heard on auscultation of the chest as a result of inflammation of the pleura with fibrinous exudate.
Excess fluid between the two membranes that envelop the lungs. These membranes are called the visceral and parietal pleurae. The visceral pleura wraps around the lung while the ...
The tiny area between the two layers of the pleura, which is normally filled with a small amount of fluid.
Rarely used synonym for pleurodynia (2). [pleur- + G. algos, pain]
A rib, or the process on a cervical or lumbar vertebra corresponding thereto. Cf.:superior articular process. [pleur- + G. apophysis, process, offshoot]
Excision of pleura, usually parietal. [pleur- + G. ektome, excision]
Inflammation of the pleura, the linings surrounding the lungs. There are two layers of pleura; one covering the lung and the other covering the inner wall of the chest. These two ...
Inflammation of the pleura. When the pleura becomes inflamed, it can produce more than the normal amount of fluid, causing a pleural effusion.
* * *
SYN: pleurisy. [G. fr. ...
Tending to produce pleurisy. [G. pleuritis, pleurisy, + genesis, origin]
SYN: pneumonocele. [ pleuro- + G. kele, hernia]
One of the lateral halves of the body of a vertebra. [ pleuro- + G. kentron, center]
Washing out of the pleural cavity. [ pleuro- + G. klysis, a washing out]
A procedure that causes the membranes around the lung to stick together and prevents the buildup of fluid in the space between the membranes. This procedure is done in cases of ...
Also known as Bornholm disease, this is a temporary illness that is a result of virus infection. The disease features fever and intense abdominal and chest pains with headache. ...
Of pleural origin; beginning in the pleura. SYN: pleurogenous (1). [ pleuro- + G. -gen, producing]
1. SYN: pleurogenic. 2. In fungi, denoting spores or conidia developed on the sides of a conidiophore or hypha.
Radiography of the pleural cavity after injecting contrast medium. [ pleuro- + G. grapho, to write]
Hepatitis with extension of the inflammation to the neighboring portion of the pleura. [ pleuro- + G. hepar, liver, + -itis, inflammation]
A concretion in the pleural cavity. SYN: pleural calculus. [ pleuro- + G. lithos, stone]
Locating pleural adhesions by the aid of an endoscope and then dividing them with the electric cautery. [ pleuro- + G. lysis, dissolution]
Combined inflammation of the pericardium and of the pleura. [ pleuro- + pericardium + G. -itis, inflammation]
Surgical resection of an entire lung along with the parietal pleura; formerly used mainly for destroyed lung due to tuberculosis; currently, a method of treating malignant ...
SYN: thoracoscopy. [ pleuro- + G. skopeo, to inspect]
SYN: thoracotomy. [ pleuro- + G. tome, incision]
Typhoid fever in which the early stage is masked by the physical signs of pleurisy.
Acronym for pityriasis lichenoides et varioliformis acuta.
Surgical excision of a plexus. [plexus + G. ektome, excision]
Weblike, or resembling or forming a plexus. [plexus + L. forma, form]
Inflammation of a plexus.
- brachial p. SYN: neuralgic amyotrophy.
Giving rise to weblike or plexiform structures. [plexus + G. -gen, producing]
Disorder involving one of the major peripheral neural plexuses: cervical, brachial, or lumbosacral. [plexus + G. pathos, disease]
SYN: plessor. [G. plexis, a stroke]
A network or interjoining of nerves and blood vessel s or of lymphatic vessels. [L. a braid]
- abdominal aortic (nervous) p. [TA] an autonomic p. surrounding the abdominal aorta, ...