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P
pivalate - planuria

pivalate (piv·a·late) (piv´ə-lāt)  USAN contraction for trimethylacetate.

pivampicillin hydrochloride (piv·am·pi·cil·lin hy·dro·chlo·ride) (piv-am”pĭ-sil´in)  a derivative of ampicillin, having the same broad spectrum of antibacterial activity and uses as ampicillin.

pivmecillinam (piv·me·cil·li·nam) (piv”mə-sil´ĭ-nəm)  INN and BAN for amdinocillin pivoxil.

pivot (piv·ot) (piv´ət)  1. that on which something turns, such as a dowel or short post.  2. the point of rotation for a removable partial denture.

occlusal p.  an elevation contrived on the occlusal surface, usually in the molar region, designed to act as a fulcrum and to induce sagittal mandibular rotation.

pixel (pix·el) (pik´sel) [contraction of pix (short for pictures) + element]  a two-dimensional region defining a unit of area on a video display screen.

pizotyline (pi·zo·ty·line) (pĭ-zo´tĭ-lēn)  an anabolic, antidepressant, and serotonin inhibitor used in treatment of migraine.

pizzle (piz·zle) (piz´əl)  popular term used in veterinary medicine for the penis of an animal.

PJRT (PJRT)  permanent junctional reciprocating tachycardia.

PJT (PJT)  paroxysmal junctional tachycardia; see paroxysmal tachycardia, under tachycardia.

PK (PK)  pyruvate kinase.

pKa (pKa)  the negative logarithm of the ionization constant of an acid (Ka); the buffering power of a buffer system is greatest when its pKa equals the pH.

PKUPKU1  (PKU), (PKU1)  phenylketonuria.

placebo (pla·ce·bo) (plə-se´bo) [L. “I will please”]  any dummy medical treatment; originally, a medicinal preparation having no specific pharmacological activity against the patient's illness or complaint given solely for the psychophysiological effects of the treatment; more recently, a dummy treatment administered to the control group in a controlled clinical trial in order that the specific and nonspecific effects of the experimental treatment can be distinguished—i.e., the experimental treatment must produce better results than the placebo in order to be considered effective.

active p. ,  impure p.  a substance having pharmacologic properties that are not relevant to the condition being treated.

placement (place·ment) (plās´mənt)  position or arrangement, as of the teeth.

lingual p.  displacement of a tooth toward the tongue.

placenta (pla·cen·ta) (plə-sen´tə)  pl. placentas, placen´tae [L. “a flat cake”]  a fetomaternal organ characteristic of true mammals during pregnancy, joining mother and offspring, providing endocrine secretion and selective exchange of soluble, bloodborne substances through an apposition of uterine and trophoblastic vascularized parts. According to species, the area of vascular apposition may be diffuse, cotyledonary, zonary, or discoid; the nature of apposition may be labyrinthine or villous; and the intimacy of apposition may vary according to what layers are lost of those originally interposed between maternal and fetal blood (maternal endothelium, uterine connective tissue, uterine epithelium, chorion, extraembryonic mesoderm, and endothelium of villous capillary). The chorion may be joined by and receive blood vessels from either the yolk sac or the allantois, and the uterine lining may be largely shed with the chorion at birth (deciduate p.) or may separate from the chorion and remain (nondeciduate p.). The human placenta is discoid, villous, hemochorial, chorioallantoic, and deciduate. After birth, it weighs about 600 g and is about 16 cm in diameter and 2 cm thick, discounting the decidua basalis and the maternal blood in the intervillous space (a principal functional part into which the chorionic villi dip and which leaks out at birth). The villi are grouped into adjoining cotyledons making about 20 velvety bumps on the side of the placenta facing the uterus; the side facing the fetus is smooth and covered with amnion, a thin avascular layer that continues past the edges of the placenta to line the entire hollow sphere of chorion except where it is reflected to cover the umbilical cord. The umbilical cord joins fetus and placenta and usually joins the placenta near the center, although it sometimes inserts at the edge, on the nonplacental chorion, or on an accessory placenta.

Click here to view image
Structural features of the placenta.

accessory p.  one separate from the main placenta.

p. accre´ta  abnormal adherence of part or all of the placenta to the uterine wall, with partial or complete absence of the decidua basalis, especially of the spongiosum layer.

adherent p.  one that adheres closely to the uterine wall.

annular p.  one which extends around the interior of the uterus like a ring or belt.

battledore p.  one with marginal insertion of the cord.

bidiscoidal p.  one consisting of two separate discoidal masses, as in the macaques.

bilobate p. ,  bilobed p.  a placenta consisting of two lobes.

p. biparti´ta ,  bipartite p.  bilobate p.

chorioallantoic p.  one in which the allantois joins the chorion or provides its major blood supply.

choriovitelline p.  one in which the yolk sac becomes an intermediary in the fetal-maternal relationship.

p. circumvalla´ta ,  circumvallate p.  a placenta in which a dense peripheral ring is raised from the surface and the attached membranes are doubled back over the edge of the placenta.

cirsoid p. ,  p. cirsoi´des  a placenta the vessels of which appear to be varicose.

deciduate p. ,  deciduous p.  a placenta or type of placentation in which the decidua or maternal parts of the placenta separate from the uterus and are cast off together with the fetal (or more precisely, trophoblastic) parts.

p. diffu´sa  a placenta in which placental tissue is distributed over the chorionic membrane, as in swine.

p. dimidia´ta ,  dimidiate p.  bilobate p.

discoid p. ,  p. discoi´dea  a disk-shaped placenta.

Duncan p.  one that is expelled with the chorionic surface outward; cf. Schultze's p.

duplex p.  bilobate p.

endotheliochorial p.  one in which syncytial trophoblast embeds maternal vessels bared to their endothelial lining.

epitheliochorial p.  one in which the uterine epithelial lining is not eroded but merely lies in apposition to the chorion.

p. fenestra´ta  one which has spots where placental tissue is lacking.

fetal p. ,  p. foeta´lis  pars fetalis placentae.

fundal p.  one attached to the fundus of the uterus in the normal manner.

furcate p.  lobed p.

hemochorial p.  one in which maternal blood comes in direct contact with the chorion, as in humans.

hemoendothelial p.  one in which maternal blood comes in contact with the endothelium of chorionic vessels.

horseshoe p.  a crescentic form of placenta sometimes occurring in twin pregnancy.

incarcerated p.  retained p.

p. incre´ta  placenta accreta with penetration of the myometrium.

labyrinthine p.  one in which maternal blood courses in channeled trophoblasts.

lobed p.  one that is more or less subdivided into lobes; called also furcate p.

maternal p.  pars uterina placentae.

p. membrana´cea  a placenta which is abnormally thin and spread out over a large area of the uterine wall.

multilobate p. ,  multilobed p. ,  p. multiparti´ta  a placenta consisting of more than three lobes.

p. nappifor´mis  p. circumvallata.

nondeciduate p. ,  nondeciduous p.  one in which the maternal component remains in the uterus instead of being cast off together with the trophoblastic derivatives.

panduriform p. ,  p. pandurifor´mis  a placenta composed of two halves side by side, resembling a violin in shape.

p. percre´ta  placenta accreta with invasion of the myometrium all the way to its peritoneal covering, sometimes invading other structures such as the bladder.

p. pre´via  a placenta which develops in the lower uterine segment, in the zone of dilatation, so that it covers or adjoins the internal os; painless hemorrhage in the last trimester, particularly during the eighth month, is the most common symptom.

p. pre´via centra´lis  central placenta previa; one in which the placenta entirely covers the internal os; called also complete or total placenta previa.

p. pre´via margina´lis  marginal placenta previa; one in which the placenta is just palpable at the margin of the os; called also lateral placenta previa.

p. pre´via partia´lis  partial placenta previa; one in which the internal os is partially covered; called also incomplete placenta previa.

p. reflex´a  one in which the margin is thickened, appearing to turn back on itself.

p. renifor´mis  a kidney-shaped placenta.

retained p.  one that is either adherent or incarcerated and in consequence fails to be expelled after childbirth.

Schultze's p.  a placenta that is delivered with the gestation sac inside out, the amnion providing a smooth, glistening surface. Cf. Duncan p.

p. spu´ria  an accessory placenta that has no blood vessel attachment to the main placenta.

p. succenturia´ta ,  succenturiate p.  an accessory portion attached to the main placenta by an artery and vein.

syndesmochorial p.  one in which the lining epithelium of the uterus is the only maternal tissue eroded.

p. tri´loba ,  trilobate p.  a placenta having three lobes.

p. triparti´ta ,  tripartite p. ,  p. trip´lex  trilobate p.

p. uteri´na ,  uterine p.  maternal p.

velamentous p.  one in which the umbilical cord is attached on the adjoining membranes.

villous p.  one characterized by the presence of villi which are outgrowths of the chorion.

yolk-sac p.  choriovitelline p.

zonary p. ,  zonular p.  1. annular p.  2. a belt-shaped placenta, as occurs in carnivores.

placental (pla·cen·tal) (plə-sen´təl)  1. pertaining to the placenta.  2. a mammal whose young receive nourishment in utero by means of a placenta.

Placentalia (Pla·cen·ta·lia) (pla”sən-ta´le-ə)  a division of mammals whose embryos are nourished through a placenta; it includes all mammals except marsupials and monotremes.

placentation (pla·cen·ta·tion) (pla”sən-ta´shən)  the process of placenta formation and the result, especially with respect to taxonomically relevant aspects of structure. See placenta.

placentitis (pla·cen·ti·tis) (pla”sən-ti´tis)  inflammation of the placenta.

placentogenesis (pla·cen·to·gen·e·sis) (plə-sen”to-jen´ə-sis) [placenta + genesis]  the origin and development of the placenta.

placentogram (pla·cen·to·gram) (plə-sen´to-gram”)  a film taken in placentography.

placentography (pla·cen·tog·ra·phy) (pla”sən-tog´rə-fe)  radiological visualization of the placenta after the injection of a contrast medium.

indirect p.  radiographic measurement of the space between the placenta and the presenting head of the fetus, for the recognition of placenta previa.

placentoid (pla·cen·toid) (plə-sen´toid)  resembling the placenta.

placentologist (pla·cen·tol·o·gist) (pla”sən-tol´ə-jist)  a specialist in placentology.

placentology (pla·cen·tol·o·gy) (pla”sən-tol´ə-je)  the scientific study of the development, structure, and functioning of the placenta.

comparative p.  the scientific study of the development, structure, and functioning of the placenta in different species of animals.

placentoma (pla·cen·to·ma) (pla”sən-to´mə)  deciduoma.

placentopathy (pla·cen·top·a·thy) (pla”sən-top´ə-the)  any disease of the placenta.

Placido's disk (Pla·ci·do's disk) (plah´se-dōz) [Antonio Placido da Costa, Portuguese ophthalmologist, 1848–1916]  see under disk.

Placidyl (Plac·i·dyl) (plas´ĭ-dəl)  trademark for a preparation of ethchlorvynol.

placode (plac·ode) (plak´ōd) [Gr. plax plate + eidos form]  a platelike structure, especially a thickened plate of ectoderm in the early embryo, from which a sense organ develops.

auditory p.  a thickened ectodermal plate located midway alongside the hindbrain in the early embryo, from which the internal ear ultimately develops. Called also auditory saucer and otic p.

dorsolateral p.’s  a series of placodes giving rise to the acoustic and lateral line organs.

epibranchial p.’s  a series of placodes located dorsal to the pharyngeal (branchial) grooves; they contribute to adjacent cerebral ganglia.

lens p.  a thickened area of ectoderm directly overlying the optic vesicle in the early embryo, from which the lens develops.

olfactory p.  an oval area of thickened ectoderm on either ventrolateral surface of the head of the early embryo, constituting the first indication of the olfactory organ.

otic p.  auditory p.

placoid (plac·oid) (plak´oid)  platelike or plaquelike.

plafond (pla·fond) (plah-fon´) [Fr. “ceiling”]  facies articularis inferior tibiae; so called from its vaulted shape.

plagiocephalic (pla·gio·ce·phal·ic) (pla”je-o-sə-fal´ik)  characterized by plagiocephaly.

plagiocephalism (pla·gio·ceph·a·lism) (pla”je-o-sef´ə-liz-əm)  plagiocephaly.

plagiocephaly (pla·gio·ceph·a·ly) (pla”je-o-sef´ə-le) [Gr. plagios oblique + -cephaly]  an unsymmetrical and twisted condition of the head, resulting from irregular closure of the cranial sutures.

plague (plague) (plāg) [L. plaga, pestis; Gr. plēgē stroke]  1. a severe acute or chronic enzootic or epizootic bacterial infection caused by Yersinia pestis, which occurs both endemically and epidemically worldwide; it is primarily a disease of urban and sylvatic rodents and is transmitted to humans by the bite of infected fleas, especially species of Leptopsylla, Nosopsylla, and Xenopsylla, or by contact with or ingestion of infected animals. Human-to-human infection usually occurs by inhalation of plague bacilli–laden droplet aerosols. The most common forms in humans are bubonic plague, pulmonic plague, and septicemic plague.  2. any of various contagious diseases in animals. Called also pest and pestis.

ambulatory p.  a mild form of bubonic plague, usually occurring only in endemic areas, with lymphadenitis, fever, headache, prostration, and a short course. Called also parapestis, pestis ambulans, and pestis minor.

avian p.  fowl p.

black p.  see bubonic p.

bubonic p.  the most common form of plague, typically characterized by abrupt onset of fever, chills, weakness, and headache, followed by pain, tenderness, and lymphadenopathy (buboes) of the regional lymph nodes, most often the inguinal, femoral, axillary, and cervical nodes, associated with a marked hemorrhagic tendency and the development of disseminated intravascular coagulation and necrotic purpura and extensive symmetrical gangrene (which may have led to the epithet “black death”). Hematogenous dissemination may establish suppurative foci throughout the body. Severe complications include pneumonia (see pneumonic p.) and septicemia (see septicemic p.). Called also glandular p., pestis bubonica, pestis fulminans, and pestis major.

cat p.  panleukopenia.

cattle p.  rinderpest.

duck p.  an acute contagious herpesvirus infection of ducks, which may also affect geese and swans. It is characterized by vascular damage, with hemorrhage into the tissues and free blood in the body cavities, exanthematous lesions of the mucosa of the digestive tract, lesions of the lymphoid organs, and retrograde changes in the parenchymatous organs. Called also duck virus enteritis.

equine p.  African horse sickness.

fowl p.  a highly contagious viral disease of domestic fowls caused by an influenza virus of serogroup A; it ranges from a mild to a fulminant, fatal infection. Characteristics include respiratory distress, sinusitis, diarrhea, bloodstained oral and nasal discharges, and edema around the head. Called also avian influenza, pest, or p. and fowl pest.

glandular p.  bubonic p.

hemorrhagic p.  see bubonic p.

meningeal p.  plague meningitis.

Pahvant Valley p.  tularemia.

pharyngeal p.  a rare form of bubonic plague that may resemble acute tonsillitis, thought to be due to inhalation or ingestion of plague bacilli. Called also plague pharyngitis.

pneumonic p. ,  pulmonic p.  a rapidly progressive, highly contagious, and often fatal pneumonia in which there is extensive involvement of the lungs and productive cough with mucoid, blood-stained, foamy, plague bacillus–laden sputum. It may occur as a primary infection, due to inhalation of droplet nuclei expelled during coughing, or as a secondary complication of bubonic plague, due to hematogenous spread of infection from buboes to the lungs; in the latter case it may subsequently be associated with human-to-human transmission and cause a primary infection. Called also plague pneumonia.

septicemic p. ,  siderating p.  acute fulminating, high-density bacteremia occurring in the acute stage of bubonic plague, or as a so-called primary infection that may present and result in death before the appearance of buboes or of pulmonic manifestations. Called also pesticemia and plague septicemia.

swine p.  hemorrhagic septicemia of swine.

sylvatic p.  bubonic plague occurring in the woods, such as that widely spread among ground squirrels and other wild rodents of the western United States.

plakins (pla·kins) (pla´kinz)  substances similar to leukins that can be extracted from blood platelets.

plana (pla·na) (pla´nə) [L.]  plural of planum.

planarian (pla·nar·i·an) (plə-nar´e-ən)  any of the free-living flatworms of the class Turbellaria, which are used extensively in biologic studies of regeneration.

Plan B (Plan B) (plan)  trademark for a preparation of levonorgestrel.

planchet (plan·chet) (plan´chət)  a metal disk on which radioactive samples are mounted and prepared for determination of radioactivity.

Planck's constant, theory (Planck's constant, theory) (plahngks) [Max Karl Ernst Ludwig Planck, German physicist, 1858–1947]  see under constant, and see quantum theory, under theory.

plane (plane) (plān) [L. planus]  1. a surface such that a straight line connecting any two of its points lies wholly in the surface. In craniotomy and cephalometry, the term plane is sometimes used interchangeably with line because when viewed from the side (lateral projection), as in a radiograph, it appears as a line.  2. a specified level, as the plane of anesthesia.  3. to rub away or abrade; see planing.  4. a superficial incision in the wall of a cavity or between tissue layers, especially in plastic surgery, made so that the precise point of entry into the cavity or between the layers can be determined.

Planes of the body, with subject in the anatomical position.


Planes of the body, with subject in the anatomical position.


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Planes of the trunk.

Addison's p.’s  a series of planes used as landmarks in the topography of the thorax and abdomen.

Aeby's p.  one passing through the nasion and basion, perpendicular to the median plane of the cranium.

auricular p. of sacral bone  facies auricularis ossis sacri.

auriculoinfraorbital p.  Frankfort horizontal p.

axial p.  one parallel with the long axis of a structure.

axiolabiolingual p.  one parallel with the long axis of an anterior tooth and passing through its labial and lingual surfaces.

axiomesiodistal p.  one parallel with the long axis of a tooth and passing through its mesial and distal surfaces.

Baer's p.  one passing through the superior borders of the zygomatic arches.

base p.  an imaginary plane upon which is estimated the retention of an artificial denture.

biparietal p.  the transverse plane that passes through the two parietal eminences.

bite p.  1. biteplane.  2. occlusal p.

Blumenbach's p.  a plane determined by the base of a skull from which the mandible has been removed.

Bolton-nasion p.  nasion-postcondylare p.

Broadbent-Bolton p.  nasion-postcondylare p.

Broca's p.  visual p.

buccolingual p.  one passing through the buccal and lingual surfaces of a posterior tooth.

coronal p.’s  plana frontalia.

cusp p.  the small imaginary plane in which buccal cusp tips and lingual cusp tips are located on posterior teeth.

Daubenton's p.  one passing through the opisthion and the inferior edges of the orbits; called also Daubenton's line.

eye-ear p.  Frankfort horizontal p.

facial p.  any of several planes passing through craniometric or cephalometric landmarks of the face.

Frankfort horizontal p.  a horizontal plane represented in profile by a line between the lowest point on the margin of the orbit and the highest point on the margin of the external acoustic (auditory) meatus.

frontal p.’s  plana frontalia.

frontoparallel p.  any plane parallel to the frontal plane.

guide p. ,  guiding p.  1. any plane that guides movement.  2. an orthodontic appliance used to correct crossbite of anterior teeth.  3. two or more vertically parallel surfaces of abutment teeth, so shaped as to direct the path of placement and removal of a partial denture.

Hensen's p.  one passing through the center of a series of sarcous elements of a muscle fibril.

Hodge's p.’s  a series of planes running parallel with the pelvic inlet, the first parallel being in the inlet, the second parallel touching the arch of the pubis and striking the inferior part of the second sacral vertebra, the third cutting the spines of the ischia, and the fourth passing through the tip of the coccyx.

horizontal p.  1. see plana horizontalia.  2. in dentistry, a plane passing through a tooth at right angles to its long axis.

interiliac p.  planum supracristale.

interparietal p. of occipital bone  planum occipitale.

interspinal p. ,  interspinous p.  planum interspinale.

intertubercular p.  planum intertuberculare.

labiolingual p.  one passing through the labial and lingual surfaces of an anterior tooth.

Listing's p.  a transverse vertical plane perpendicular to the anteroposterior axis of the eye, and containing the center of motion of the eyes; in it lie the transverse and vertical axes of ocular rotation.

longitudinal p.  any plane parallel to the long axis of the body or of an organ.

Ludwig's p.  a horizontal plane transecting the trunk at about the level of the joint between the fourth and fifth thoracic vertebrae.

mean foundation p.  the mean of the various irregularities in form and inclination of the basal seat (denture-supporting tissues). The ideal condition for denture stability exists when the mean foundation plane is most nearly at right angles to the direction of force.

Meckel's p.  one passing through the auricular and alveolar points.

median p.  planum medianum.

median-raphe p.  the median plane of the head.

median sagittal p.  planum medianum.

mesiodistal p.  one passing through the mesial and distal surfaces of a tooth.

midclavicular p.  linea medioclavicularis.

midpelvic p.  pelvic p., narrow.

midsagittal p.  planum medianum.

Morton's p.  one passing through the most projecting points of the parietal and occipital protuberances.

nasal p.  the flat area between the nostrils on the muzzle of an animal. Called also planum nasale.

nasion-postcondylare p.  one passing at right angles to the median plane, and determined in profile by a line connecting the nasion and postcondylare.

nuchal p.  planum nuchale.

occipital p.  planum occipitale.

occlusal p. ,  p. of occlusion  the hypothetical horizontal plane formed by the contacting surfaces of the upper and lower teeth when the jaws are closed.

orbital p.  1. a plane passing through the two orbital points and perpendicular to the Frankfort horizontal plane; called also planum orbitale.  2. visual p.

orbital p. of frontal bone  pars orbitalis ossis frontalis.

paramedian p.’s  plana paramediana.

parasagittal p.  sagittal p's.

pelvic p.  one determined by certain landmarks of the hip bone.

pelvic p., narrow  an ovoid plane passing through the apex of the pubic arch, the spines of the ischia, and the end of the sacrum.

pelvic p., wide  an irregularly ovoid plane passing from the middle of the pubis to the junction of the second and third sacral vertebrae, at about the center of the excavation of the pelvis.

pelvic p. of outlet  a plane passing through the arch of the pubis, the rami of the pubis, the ischial tuberosities, and the tip of the coccyx; see apertura pelvis inferior.

popliteal p. of femur  facies poplitea femoris.

principal p.  in radiology, the plane which contains the central ray of a radiation beam.

p.’s of reference  planes which are referred to as a guide to the location of specific anatomical sites, or of other planes.

p. of regard  one passing through the center of rotation and the point of fixation in the eye.

sagittal p.’s  plana sagittalia.

semicircular p. of frontal bone  facies temporalis ossis frontalis.

semicircular p. of parietal bone  planum temporale.

semicircular p. of squama temporalis  facies temporalis partis squamosae.

spinous p.  a horizontal plane transecting the trunk at the level of the anterior superior iliac spine.

sternal p.  planum sternale.

sternoxiphoid p.  a horizontal plane transecting the trunk at about the level of the xiphisternal joint.

subcostal p.  planum subcostale.

supracrestal p. ,  supracristal p.  planum supracristale.

suprasternal p.  a horizontal plane transecting the trunk at the level of the jugular notch.

temporal p.  planum temporale.

thoracic p.  a horizontal plane transecting the trunk at about the level of the fourth intercostal space.

tooth p.  any hypothetical plane passing through a tooth.

transpyloric p.  planum transpyloricum.

transtubercular p.  planum intertuberculare.

transverse p.’s  plana transversalia.

umbilical p.  a horizontal plane transecting the trunk at the level of the umbilicus.

vertical p.  any plane of the body perpendicular to a horizontal plane and dividing the body into left and right, or front and back portions, as the sagittal and frontal planes.

visual p.  one passing through the visual axes of the two eyes; called also Broca's p. and orbital p.

planigram (pla·ni·gram) (pla´nĭ-gram)  tomogram.

planigraphy (pla·nig·ra·phy) (plə-nig´rə-fe)  tomography.

planimeter (pla·nim·e·ter) (plə-nim´ə-tər) [L. planus plane + -meter]  an instrument used in measuring the area of surfaces.

planing (plan·ing) (plān´ing)  1. the plastic surgery procedure of abrading disfigured skin to promote reepithelialization with minimal scarring. It may be done by means of sandpaper, emery paper, low- or high-speed wire brushes, etc. (surgical planing; dermabrasion), or by application of caustic substances such as phenol or trichloroacetic acid (chemical planing; chemabrasion).  2. see root p.

root p.  smoothing of the root surface of a tooth after subgingival scaling or curettage.

planithorax (plani·tho·rax) (plan”ĭ-thor´aks)  a diagram of the front and back of the chest.

plankton (plank·ton) (plank´ton) [Gr. planktos wandering]  a collective name for the minute free-floating organisms, vegetable and animal, which live in practically all natural waters.

planocellular (pla·no·cel·lu·lar) (pla”no-sel´u-lər)  made up of flat cells.

planoconcave (pla·no·con·cave) (pla”no-kon´kāv)  flat on one side and concave on the other; see under lens.

planoconvex (pla·no·con·vex) (pla”no-kon´veks)  flat on one side and convex on the other; see under lens.

planocyte (pla·no·cyte) (pla´no-sīt) [Gr. planē wandering + -cyte]  ameboid cell.

planorbid (pla·nor·bid) (plə-nor´bid)  1. a snail of the family Planorbidae.  2. pertaining to snails of the family Planorbidae.

Planorbidae (Pla·nor·bi·dae) (plə-nor´bĭ-de) [L. planus flat + orbis ring + -idae]  a large family of pulmonate fresh-water snails (suborder Basommatophora, order Pulmonata), many species of which are intermediate hosts of pathogenic trematodes; it includes the genera Biomphalaria, Bulinus, Segmentina, and Planorbis (the type genus).

Planorbis (Pla·nor·bis) (plə-nor´bis)  a genus of snails of the family Planorbidae. Several species act as intermediate hosts for trematodes such as Schistosoma mansoni, Fasciolopsis buski, and species of Echinostoma.

plant (plant) (plant)  any multicellular eukaryotic organism that performs photosynthesis to obtain its nutrition; plants comprise one of the five kingdoms in the most widely used classification of living organisms.

planta (plan·ta) (plan´tə) [L.]   [TA] sole: the undersurface of the foot. Called also regio plantaris [TA alternative].

p. pe´dis  former name for planta.

plantaginis semen (plan·tag·i·nis se·men) (plan-taj´ĭ-nis se´mən) [L.]  plantago seed.

Plantago (Plan·ta·go) (plan-ta´go)  the psylliums, a genus of herbs of the family Plantaginaceae whose seeds are used medicinally. There are three important species, P. in´dica L., P. ova´ta Forskal (blond psyllium), and P. psyl´lium L. (Spanish psyllium). See also plantago seed, under seed, psyllium husk, under husk, and psyllium hydrophilic mucilloid, under mucilloid.

plantalgia (plan·tal·gia) (plan-tal´jə) [L. planta sole + -algia]  a painful condition of the sole of the foot.

plantar (plan·tar) (plan´tər)  pertaining to the sole of the foot.

plantaris (plan·ta·ris) (plan-ta´ris) [L., from planta sole of the foot]   [TA] plantar; a term designating relationship to the sole of the foot.

plantation (plan·ta·tion) (plan-ta´shən) [L. plantare to plant]  the insertion or application of tissue, such as a tooth, or of other material, in or on the human body. Types include implantation, replantation, and transplantation.

plantigrade (plan·ti·grade) (plan´tĭ-grād) [L. planta sole + gradi to walk]  characterized by walking on the full sole of the foot; said of animals such as bears and humans. Cf. digitigrade and unguligrade.

planula (plan·u·la) (plan´u-lə)  1. a larval coelenterate.  2. something resembling such an animal.

invaginate p.  gastrula.

planum (pla·num) (pla´nəm)  pl. pla´na [L.]  1. plane.  2. in anatomical nomenclature, a more or less flat surface of a bone or other structure.

pla´na corona´lia  TA alternative for plana frontalia

pla´na fronta´lia  [TA]  frontal planes: planes passing longitudinally through the body from side to side, at right angles to the median plane, and dividing the body into front and back parts. So called because such planes roughly parallel the frontal suture of the skull. Called also plana coronalia or coronal planes because one of these planes passes through the coronal suture.

pla´na horizonta´lia  [TA]  horizontal planes: planes at right angles to the long axis of the body.

p. interspina´le  [TA]  interspinous plane: a horizontal plane transecting the trunk at the level of the anterior superior iliac spines; called also interspinal line or plane.

p. intertubercula´re  [TA]  intertubercular plane: a horizontal plane transecting the trunk at the level of the iliac tubercles; called also intertubercular line.

pla´na, li´neae, et regio´nes  planes, lines, and regions: a section of the Terminologia Anatomica that contains terms used to describe the surface anatomy of the body.

p. media´num  [TA]  median plane: the imaginary plane passing longitudinally through the middle of the body from front to back and dividing it into right and left halves. Called also median sagittal and midsagittal plane.

p. nasa´le  nasal plane.

p. nucha´le  nuchal plane: the outer surface of the occipital bone between the foramen magnum and the superior nuchal line.

p. occipita´le  [TA]  occipital plane: the outer surface of the occipital bone superior to the superior nuchal line.

p. orbita´le  orbital plane (def. 1).

pla´na paramedia´na  [TA]  paramedian planes: sagittal planes other than the median plane.

p. popli´teum fe´moris  facies poplitea femoris.

pla´na sagitta´lia  [TA]  sagittal planes: vertical planes that pass through the body parallel to the median plane (or to the sagittal suture) and divide the body into left and right portions. Included here are the median and paramedian planes.

p. semiluna´tum  the rounded end of a crista ampullaris in a semicircular canal.

p. sterna´le  sternal plane: the anterior surface of the sternum.

p. subcosta´le  [TA]  subcostal plane: a horizontal plane transecting the trunk at the level of the inferior margins of the tenth costal cartilages; called also infracostal line.

p. supracrista´le  [TA]  supracristal plane: a horizontal plane transecting the trunk at the summits of the iliac crests at the level of the fourth lumbar spinous process; called also supracrestal line or plane and interiliac plane.

p. tempora´le  [TA]  temporal plane: the depressed area on the side of the skull inferior to the inferior temporal line.

p. transpylo´ricum  [TA]  transpyloric plane: a horizontal plane half way between the superior margins of the manubrium sterni and the pubic symphysis, which usually does not correspond to the level of the pylorus.

pla´na trans´versalia  [TA]  transverse planes: horizontal planes of the body dividing the body into superior and inferior portions.

planuria (pla·nu·ria) (pla-nu´re-ə) [Gr. planasthai to wander + -uria]  the discharge of urine from an abnormal site.


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