| crown of Venus | Papular lesions of secondary syphilis on the forehead near the hair margin. See: collar of Venus. (05 Mar 2000) |
|---|---|
| crown-rump length | In utero measurement corresponding to the sitting height (crown to rump) of the foetus. Length is considered a more accurate criterion of the age of the foetus than is the weight. The average crown-rump length of the foetus at term is 36 cm. (12 Dec 1998) |
| crown tubercle | Tubercle of cuneate nucleus, the bulbous rostral extremity of the fasciculus cuneatus corresponding to the position of the cunate nucleus, lying lateral to the clava and separated from the tuberculum cinereum on its lateral side by the posterior lateral sulcus. Synonym: tuberculum nuclei cuneati, tuberculum cuneatum, wedge-shaped tubercle. (05 Mar 2000) |
| tooth crown | The upper part of the tooth, which joins the lower part of the tooth (tooth root) at the cervix (tooth cervix) at a line called the cementoenamel junction. The entire surface of the crown is covered with enamel which is thicker at the extremity and becomes progressively thinner toward the cervix. (12 Dec 1998) |
| jacket crown | A hollow crown of acrylic resin, fused porcelain or cast gold, combinations of gold and acrylic or gold and porcelain; it fits over the prepared stump of the natural crown. (05 Mar 2000) |
| active metal | <chemistry> Any very reactive metal, such as magnesium or sodium, most are located in the first two columns of the periodic table. (15 Jan 1998) |
| alkali earth metal | See: alkaline earth elements. (05 Mar 2000) |
| alkali metal | <chemistry> Any of the highly reactive metals (such as sodium or potassium) found in the first column of the periodic table, these metals act as bases. (13 Nov 1997) |
| Babbitt metal | An alloy of antimony, copper, and tin; used occasionally in dentistry. (05 Mar 2000) |
| base metal | A metal that is readily oxidised; e.g., iron, copper. (05 Mar 2000) |
| bell metal | A hard alloy or bronze, consisting usually of about three parts of copper to one of tin; used for making bells. Bell metal ore, a sulphide of tin, copper, and iron; the mineral stannite. Source: Websters Dictionary (01 Mar 1998) |
| rare earth metal | Those elements with atomic numbers 57-71 which closely resemble one another chemically and were once difficult to separate from one another. Synonym: rare earth elements. Origin: Lanthanum, first element of the series (05 Mar 2000) |
| central metal ion | <chemistry> The metal ion to which the ligands are attached at the centre of a coordination complex. (09 Oct 1997) |
| void metal composite | A porous metal structure that enables tissue growth within the openings to establish long-term attachment between prosthesis and tissue. (05 Mar 2000) |
| respiratory metal | A metal present in certain respiratory pigments; e.g., iron, manganese, copper, vanadium. (05 Mar 2000) |