| pelvic plane of least dimensions | The plane that extends from the end of the sacrum to the inferior border of the pubic symphysis; it is bounded posteriorly by the end of the sacrum, laterally by the ischial spines, and anteriorly by the inferior border of the pubic symphysis. Synonym: midplane, plane of least pelvic dimensions, plane of midpelvis, third parallel pelvic plane. (05 Mar 2000) |
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| pelvic plane of outlet | The lower opening of the true pelvis, bounded anteriorly by the pubic arch, laterally by the rami of the ischium and the sacrotuberous ligament on either side, and posteriorly by these ligaments and the tip of the coccyx. Synonym: apertura pelvis inferior, apertura pelvis minoris, fourth parallel pelvic plane, pelvic outlet, pelvic plane of outlet, plane of outlet. (05 Mar 2000) |
| guide plane | A fixed or removable device used to displace a single tooth, an arch segment, or an entire arch toward an improved relationship. (05 Mar 2000) |
| midsagittal plane | A vertical plane through the midline of the body that divides the body into right and left halves. See: Addison's clinical planes. Synonym: midsagittal plane. (05 Mar 2000) |
| Morton's plane | A plane passing through the summits of the parietal and occipital protuberances. (05 Mar 2000) |
| plane | 1. To make smooth; to level; to pare off the inequalities of the surface of, as of a board or other piece of wood, by the use of a plane; as, to plane a plank. 2. To efface or remove. "He planed away the names . . . Written on his tables." (Chaucer) 3. Figuratively, to make plain or smooth. "What student came but that you planed her path." (Tennyson) Origin: Cf. F. Planer, L. Planare, fr. Planus. See Plane, Plain, and cf. Planish. <botany> Any tree of the genus Platanus. The Oriental plane (Platanus orientalis) is a native of Asia. It rises with a straight, smooth, branching stem to a great height, with palmated leaves, and long pendulous peduncles, sustaining several heads of small close-sitting flowers. The seeds are downy, and collected into round, rough, hard balls. The Occidental plane (Platanus occidentalis), which grows to a great height, is a native of North America, where it is popularly called sycamore, buttonwood, and buttonball, names also applied to the California species (Platanus racemosa). Origin: F, fr. L. Platanus, Gr, fr. Broad; so called on account of its broad leaves and spreading form. See Place, and cf. Platane, Plantain the tree. Without elevations or depressions; even; level; flat; lying in, or constituting, a plane; as, a plane surface. In science, this word (instead of plain) is almost exclusively used to designate a flat or level surface. Plane angle, the angle included between two straight lines in a plane. Plane chart, Plane curve. See Chart and Curve. Plane figure, a figure all points of which lie in the same plane. If bounded by straight lines it is a rectilinear plane figure, if by curved lines it is a curvilinear plane figure. Plane geometry, that part of geometry which treats of the relations and properties of plane figures. Plane problem, a problem which can be solved geometrically by the aid of the right line and circle only. Plane sailing, a scale for the use of navigators, on which are graduated chords, sines, tangents, secants, rhumbs, geographical miles, etc. Plane surveying, surveying in which the curvature of the earth is disregarded; ordinary field and topographical surveying of tracts of moderate extent. Plane table, an instrument used for plotting the lines of a survey on paper in the field. Plane trigonometry, the branch of trigonometry in which its principles are applied to plane triangles. Origin: L. Planus: cf. F. Plan. See Plan. 1. <geometry> A surface, real or imaginary, in which, if any two points are taken, the straight line which joins them lies wholly in that surface; or a surface, any section of which by a like surface is a straight line; a surface without curvature. 2. <astronomy> An ideal surface, conceived as coinciding with, or containing, some designated astronomical line, circle, or other curve; as, the plane of an orbit; the plane of the ecliptic, or of the equator. 3. <mechanics> A block or plate having a perfectly flat surface, used as a standard of flatness; a surface plate. 4. A tool for smoothing boards or other surfaces of wood, for forming moldings, etc. It consists of a smooth-soled stock, usually of wood, from the under side or face of which projects slightly the steel cutting edge of a chisel, called the iron, which inclines backward, with an apperture in front for the escape of shavings; as, the jack plane; the smoothing plane; the molding plane, etc. <geometry> Objective plane, the plane in which lie both the incident ray and the refracted or reflected ray. Origin: F. Plane, L. Plana. See Plane, &. Source: Websters Dictionary (01 Mar 1998) |
| plane, focal | <microscopy> A plane through the focal point perpendicular to the principle axis of a lens or mirror. (05 Aug 1998) |
| plane joint | A synovial joint in which the opposing surfaces are nearly planes and in which there is only a slight, gliding motion, as in the intermetacarpal joints. Synonym: articulatio plana, arthrodia, arthrodial articulation, arthrodial joint, gliding joint. (05 Mar 2000) |
| plane of incidence | The plane perpendicular to a lens surface that contains the incident light ray. (05 Mar 2000) |
| plane of inlet | The upper opening of the true pelvis, bounded anteriorly by the pubic symphysis and the pubic crest on either side, laterally by the iliopectineal lines, and posteriorly by the promontory of the sacrum. Synonym: apertura pelvis superior, aditus pelvis, first parallel pelvic plane, pelvic brim, pelvic inlet, pelvic plane of inlet, plane of inlet. (05 Mar 2000) |
| plane of least pelvic dimensions | The plane that extends from the end of the sacrum to the inferior border of the pubic symphysis; it is bounded posteriorly by the end of the sacrum, laterally by the ischial spines, and anteriorly by the inferior border of the pubic symphysis. Synonym: midplane, plane of least pelvic dimensions, plane of midpelvis, third parallel pelvic plane. (05 Mar 2000) |
| plane of midpelvis | The plane that extends from the end of the sacrum to the inferior border of the pubic symphysis; it is bounded posteriorly by the end of the sacrum, laterally by the ischial spines, and anteriorly by the inferior border of the pubic symphysis. Synonym: midplane, plane of least pelvic dimensions, plane of midpelvis, third parallel pelvic plane. (05 Mar 2000) |
| plane of outlet | The lower opening of the true pelvis, bounded anteriorly by the pubic arch, laterally by the rami of the ischium and the sacrotuberous ligament on either side, and posteriorly by these ligaments and the tip of the coccyx. Synonym: apertura pelvis inferior, apertura pelvis minoris, fourth parallel pelvic plane, pelvic outlet, pelvic plane of outlet, plane of outlet. (05 Mar 2000) |
| plane of pelvic canal | A hypothetical curved line joining the centre point of each of the four planes of the pelvis, marking the centre of the pelvic cavity at every level. Synonym: axis pelvis, plane of pelvic canal. (05 Mar 2000) |
| plane of regard | An imaginary plane through which the point of regard moves as the eyes are turned from side to side. (05 Mar 2000) |