| vertex | 1. <anatomy> A turning point; the principal or highest point; top; summit; crown; apex. Specifically: the top, or crown, of the head. 2. <astronomy> The zenith, or the point of the heavens directly overhead. 3. <mathematics> The point in any figure opposite to, and farthest from, the base; the terminating point of some particular line or lines in a figure or a curve; the top, or the point opposite the base. Vertex of a curve, the point in which the axis pierces the surface. The principal vertex of a conic section is, in the parabola, the vertex of the axis of the curve: in the ellipse, either extremity of either axis, but usually the left-hand vertex of the transverse axis; in the hyperbola, either vertex, but usually the right-hand vertex of the transverse axis. Origin: L. Vertex, -icis, a whirl, top of the head, top, summit, from vertere to turn. See Verse, and cf. Vortex. (29 Oct 1998) |
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| vertex cordis | The blunt extremity of the heart formed by the left ventricle. See: apex beat. Synonym: apex cordis, vertex cordis. (05 Mar 2000) |
| vertex corneae | The central part of the cornea, slightly thinner than the peripheral part. Synonym: vertex corneae. (05 Mar 2000) |
| vertex of cornea | The central part of the cornea, slightly thinner than the peripheral part. Synonym: vertex corneae. (05 Mar 2000) |
| vertex presentation | See: cephalic presentation. (05 Mar 2000) |
| presentation, vertex | In a vertex presentation, the top of the baby's head comes first at delivery. The vertex here refers specifically to the top of the head the word vertex in latin means a whirlpool, whirlwind, top of the mountain, or the top of the head. Why top of the head ? because the hairs on the top of the head often form a whorl, a whirl-like pattern. (12 Dec 1998) |
| submental vertex projection | Radiographic projection devised to obtain direct visualization of the base of the skull. Synonym: axial view, base projection, submental vertex projection, submentovertical projection, verticosubmental view. (05 Mar 2000) |
| submental vertex radiograph | A radiographic projection showing the base of the skull, positions of the mandibular condyles, and zygomatic arches. Synonym: base view, submental vertex radiograph. (05 Mar 2000) |
| delivery, vertex | In a vertex delivery, the top of the baby's head comes first. The vertex here refers to the top of the head The word vertex in Latin means a whirlpool, whirlwind, top of the mountain, or the top of the head. Why top of the head ? Because the hairs on the top of the head often form a whorl, a whirl-like pattern. (12 Dec 1998) |
| map distance | The degree of separation of two loci on a linkage map, measured in morgans or centimorgans. (05 Mar 2000) |
| genetic distance | <molecular biology> A way of measuring the amount of evolutionary divergence in two separated populations of a species by counting the number of allelic substitutions per locus that have cropped up in each population. (09 Oct 1997) |
| reduced interarch distance | An occluding vertical dimension which results in an excessive interocclusal distance when the mandible is in rest position, and in a reduced interridge distance when the teeth are in contact. (05 Mar 2000) |
| working distance free | <microscopy> The distance between the front lens of the objective and the coverslip (or uncovered object) when the lens is focused on the specimen. (05 Aug 1998) |
| pupillary distance | The distance between the centre of each pupil; the major reference points in measuring for fitting of spectacle frames and lenses. (05 Mar 2000) |
| hyperfocal distance | <microscopy> The nearest distance, h, at which a camera lens focuses the far distance (infinity). This gives the maximum depth of field, the nearest distance in focus is h/2. (05 Aug 1998) |