| trace elements | A group of chemical elements that are needed in minute quantities for the proper growth, development, and physiology of an organism. (12 Dec 1998) |
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| trace nutrient | Essential dietary elements required only in small quantities. They are present in the body in amounts less than .005% of body weight. (12 Dec 1998) |
| tracer | 1. An element or compound containing atoms that can be distinguished from their normal counterparts by physical means (e.g., radioactivity assay or mass spectrography) and can thus be used to follow (trace) the metabolism of the normal substances. 2. A coloured substance (e.g., a dye) used as a tracer to follow the flow of water. 3. An instrument used in dissecting out nerves and blood vessels. 4. A mechanical device with a marking point attached to one jaw and a graph plate or tracing plate attached to the other jaw; used to record the direction and extent of movements of the mandible. See: tracing. Origin: M.E. Track, fr. O. Fr. Tracier, to make one's way, fr. L. Traho, pp. Tractum, to draw, + -er, agent suffix (05 Mar 2000) |
| tracer/y | Ornamental work with rambled lines. Especially: The decorative head of a Gothic window. Window tracery is of two sorts, plate tracery and bar tracery. Plate tracery, common in Italy, consists of a series of ornamental patterns cut through a flat plate of stone. Bar tracery is a decorative pattern formed by the curves and intersections of the molded bars of the mullions. Window tracery is imitated in many decorative objects, as panels of wood or metal either pierced or in relief. See also Stump tracery under Stump, and Fan tracery under Fan. A similar decoration in some styles of vaulting, the ribs of the vault giving off the minor bars of which the tracery is composed. Source: Websters Dictionary (01 Mar 1998) |
| trachea | The windpipe. A fibrocartilaginous tube lined with mucous membrane passing from the larynx to the bronchi. (27 Sep 1997) |
| tracheal | Relating to the trachea. (05 Mar 2000) |
| tracheal branches | Branches to the trachea. Nomina Anatomica lists tracheal branches of 1) inferior thyroid artery (rami tracheales arteriae thyroideae inferioris ); and 2) recurrent laryngeal nerve (rami tracheales nervi laryngei recurrentis ). Synonym: rami tracheales. (05 Mar 2000) |
| tracheal cartilages | The 16 to 20 incomplete rings of hyaline cartilage forming the skeleton of the trachea; the rings are deficient posteriorly for from one-fifth to one-third of their circumference. Synonym: cartilagines tracheales, tracheal ring. (05 Mar 2000) |
| tracheal fenestration | A surgical procedure to create an epithelialised mucocutaneous opening from the neck into the trachea. (05 Mar 2000) |
| tracheal fistula | A form of fistula colli congenita. (05 Mar 2000) |
| tracheal glands | Numerous tubuloalveolar mixed glands located principally in the submucosa of the trachea; they open into the tracheal lumen through short ducts. Synonym: glandulae tracheales. (05 Mar 2000) |
| tracheal intubation | Passage of a tube through the nose, mouth, or a tracheotomy into the trachea for maintenance of patency of the airway. (05 Mar 2000) |
| tracheal lymph nodes | Nodes along the sides of the trachea in the neck and in the posterior mediastinum; receive drainage of superior (and inferior) tracheobranchial (nodes, trachea and oesophagus); drain to bronchomediastinal lymphatic trunk(s), thoracic duct. Synonym: nodi lymphatici paratracheales, tracheal lymph nodes. (05 Mar 2000) |
| tracheal mucosa | The inner mucous layer of the trachea. Synonym: tunica mucosa tracheae. (05 Mar 2000) |
| tracheal ring | The 16 to 20 incomplete rings of hyaline cartilage forming the skeleton of the trachea; the rings are deficient posteriorly for from one-fifth to one-third of their circumference. Synonym: cartilagines tracheales, tracheal ring. (05 Mar 2000) |