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Medical Dictionary


tripeptide (tri-pep′tid)
A compound containing three amino acids linked together by peptide bonds.

triphalangia (tri-fa-lan′je-a)
Malformation in which three phalanges are present in the thumb or great toe. [tri- + phalanx]

Léon, French surgeon, 1842–1891. See T. amputation.

triplant (tri′plant)
See t. implant.

triplegia (tri-ple′je-a)
1. Paralysis of three limbs, both extremities on one side and one on the other. 2. Paralysis of an upper and a lower extremity and of the face. [tri- + G. plege, stroke]

1. One of three children delivered at the same birth. SYN: tridymus. 2. A set of three similar objects, as a compound lens in a microscope, formed of three planoconvex lenses. 3. SYN: codon. nonsense t. 1. a trinucleotide (codon) in which a base change to a termination codon results in premature termination of the growing polypeptide chain and, consequently, incomplete protein molecules; 2. a termination codon.

triploblastic (trip-lo-blas′tik)
Formed of three primary germ layers (ectoderm, mesoderm, endoderm), or containing tissue derived from all three layers. [G. triploos, threefold, + blastos, germ]

triploid (trip′loyd)
Pertaining to or characteristic of triploidy. [tri- + -ploid]

triploidy (trip′loy-de)
The presence of three haploid sets of chromosomes, instead of two, in all cells; results in fetal or neonatal death.

triplopia (trip-lo′pe-a)
Visual defect in which three images of the same object are seen. SYN: triple vision. [G. triploos, triple, + opsis, sight]

tripod (tri′pod)
1. Three-legged. 2. A stand having three legs or supports. [G. tripous, fr. tri- + pous, foot] Haller t. SYN: celiac (arterial) trunk. vital t. the brain, the heart, and the lungs, regarded as the three organs essential to life.

tripodia (tri-po′de-a)
Condition in conjoined twins in which the lower extremities on the joined sides form a single foot, so that there are only three feet for the two bodies. See conjoined twins, under twin. [tri- + G. pous, foot]

triprolidine hydrochloride (tri-prol′i-den)
An H1 antihistaminic used in the management of allergic and pruritic conditions.

triprosopus (tri′pro-so′pus)
Fetus with three united heads, with only parts of three faces. [tri- + G. prosopon, face]

tripsis (trip′sis)
1. SYN: trituration (1) . 2. SYN: massage. [G. a rubbing]

triquetrous (tri-kwe′trus, -kwet-)
Triangular. [L. triquetrus, three-cornered]

triquetrum (tri-kwe′trum, -kwet-) [TA]
A bone on the medial (ulnar) side of the proximal row of the carpus, articulating with the lunate, pisiform, and hamate. SYN: os t. [TA] , cubital bone, os pyramidale, os triangulare, pyramidal bone, pyramidale, three-cornered bone, t. bone. [L. triquetrus, three-cornered]

triradial, triradiate (tri-ra′de-al, tri-ra′de-at)
Radiating in three directions.

triradius (tri-ra′de-us)
In dermatoglyphics, the figure at the base of each finger in the palm, produced by rows of papillae running in three directions so as to form a triangle. SYN: Galton delta (2) .

Abbreviation for t.(hydroxymethyl)aminomethane and t.(hydroxymethyl)methylamine; used as a trivial name.

Chemical prefix indicating three of the substituents that follow, independently linked. Cf.:tri-.

trisaccharide (tri-sak′a-rid)
A carbohydrate containing three monosaccharide residues, e.g., raffinose.

tris(hydroxymethyl)aminomethane (Tris)
SYN: tromethamine.

tris(hydroxymethyl)methylamine (Tris)
SYN: tromethamine.

triskaidekaphobia (tris′ki-dek-a-fo′be-a)
Superstitious dread of the number 13. [G. triskaideka, thirteen, + phobos, fear]

trismic (triz′mik)
Relating to or marked by trismus.

trismoid (triz′moyd)
1. Resembling trismus. 2. Trismus nascentium, formerly regarded as a distinct variety due to pressure on the occiput during birth. [trismus + G. eidos, resemblance]

trismus (triz′mus)
Persistent contraction of the masseter muscles due to failure of central inhibition; often the initial manifestation of generalized tetanus. SYN: Ankylostoma (2) , lock-jaw, lockjaw. [L. fr. G. trismos, a creaking, rasping] t. capistratus congenital adhesion of the cheeks to the gums. t. nascentium stiffness of the jaw muscles in neonates, usually as the beginning of tetanus neonatorum. SYN: t. neonatorum. t. neonatorum SYN: t. nascentium. t. sardonicus SYN: risus caninus.

trisomic (tri-so′mik)
Relating to trisomy.

trisomy (tri′so-me)
The state of an individual or cell with an extra chromosome instead of the normal pair of homologous chromosomes; in humans, the state of a cell containing 47 normal chromosomes.For various types of t. syndrome, see under syndrome. [tri- + (chromo)some]

trisplanchnic (tri-splangk′nik)
Relating to the three visceral cavities: skull, thorax, and abdomen. [tri- + G. splanchnon, viscus]

tristearin (tri-ste′a-rin)
SYN: stearin.

tristichia (tri-stik′i-a)
Presence of three rows of eyelashes. [G. tristichos, in three rows, fr. tri-, three, + stichos, row]

trisulcate (tri-sul′kat)
Marked by three grooves.

tritanomaly (tri′ta-nom′a-le)
A type of partial color deficiency due to a deficiency or abnormality of blue-sensitive retinal cones. [G. tritos, third, + anomalia, irregularity]

tritanopia (tri′ta-no′pe-a)
Deficient color perception in which there is an absence of blue-sensitive pigment in the retinal cones. [G. tritos, third, + an- priv. + ops, eye]

triterpenes (tri-ter′penz)
Hydrocarbons or their derivatives formed by the condensation of six isoprene units (equivalent to three terpene units) and containing, therefore, 30 carbon atoms; e.g., squalene, certain steroids, cardiac glycosides.

tritiated (trit′e-a-ted)
Containing atoms of tritium (hydrogen-3) in the molecule.

triticeoglossus (tri-tish′e-o-glos′us)
See musculus t.. [L. triticeum, + G. glossa, tongue]

triticeous (tri-tish′us)
Resembling or shaped like a grain of wheat. [L. triticeus, fr. triticum, a grain of wheat]

triticeum (tri-tish′e-um)
SYN: triticeal cartilage. [L. triticeus, triticeous, like a grain of wheat]

tritium (T, t) (trit′e-um, trish′-)
SYN: hydrogen-3.

Tritrichomonas (tri′trik-o-mo′nas)
A genus of parasitic protozoan flagellates, formerly part of the genus Trichomonas but now separated as a distinct genus by the absence of a pelta and the presence of three anterior flagella. Species include T. foetus, which causes bovine trichomoniasis, and T. suis, which occurs in the nasal passages, stomach, cecum, and colon of pigs. SEE ALSO: Trichomonas. [G. tri-, three, + Trichomonas]

tritubercular (tri-too-ber′ku-lar)
SYN: tricuspid (2) .

triturable (trit′u-ra-bl)
Capable of being triturated.

triturate (trit′u-rat)
1. To accomplish trituration. 2. A triturated substance.

trituration (trit-u-ra′shun)
1. The act of reducing a drug to a fine powder and incorporating it thoroughly with sugar of milk by rubbing the two together in a mortar. SYN: tripsis (1) . 2. Mixing of dental amalgam in a mortar and pestle or with a mechanical device. [L. trituratio, fr. trituro, to thresh, fr. tero, pp. tritus, to rub]

trityl (tri′til)
The triphenylmethyl radical, Ph3C–.

trivalence, trivalency (tri-va′lens, -len-se)
The property of being trivalent.

trivalent (tri-va′lent)
Having the combining power (valence) of 3.

trivalve (tri′valv)
Provided with three valves, as a speculum with three diverging blades.

trivial name
A name of a chemical, no part of which is necessarily used in a systematic sense; i.e., it gives little or no indication as to chemical structure. Such names are common for drugs, hormones, proteins, and other biologicals, and are used by the general public. They may not be officially sanctioned, in contrast to nonproprietary names, but may be adopted as official nonproprietary names as a result of widespread usage. Examples are water, aspirin, chlorophyll, heme, methotrexate, folic acid, caffeine, thyroxine, epinephrine, barbital, etc.; also common abbreviations for chemically defined substances, such as ACTH, MSH, BAL, DDT, which are spoken as such and not in terms of the words they represent. The distinction between trivial and semitrivial names is seldom made; thus tetrahydrofolate, methylglycine, glucosamine, etc., are often termed trivial even though each contains a systematic part that is used in the correct systematic sense (tetrahydro for four hydrogen atoms, methyl for a –CH3 group, amine for –NH2 in the above examples). Trivial names are often assigned arbitrarily to chemical compounds, especially from natural sources, before the chemical structures, hence systematic names can be assigned. Also, they afford useful shortenings of long systematic names even when these can be stated (although most such shortenings turn out to be semisystematic, as they incorporate some portion of the systematic name).

trizonal (tri-zo′nal)
Having, or arranged in, three zones or layers.

Abbreviation for transfer RNA.

trocar (tro′kar)
An instrument for withdrawing fluid from a cavity, or for use in paracentesis; it consists of a metal tube (cannula) into which fits an obturator with a sharp three-cornered tip, which is withdrawn after the instrument has been pushed into the cavity; the name t. is usually applied to the obturator alone, the entire instrument being designated t. and cannula. [Fr. trocart, fr. trois, three, + carre, side (of a sword blade)] Hasson t. a blunt t. inserted into the peritoneal cavity after making a small celiotomy; used for insufflation and introduction of a laparoscope.

Abbreviation for trochiscus.

trochanter (tro-kan′ter)
One of the bony prominences developed from independent osseous centers near the upper extremity of the femur; there are two in humans, three in the horse. [G. t., a runner, fr. trecho, to run] greater t. [TA] a strong process at the proximal and lateral part of the shaft of the femur, overhanging the root of the neck; it gives attachment to the gluteus medius and minimus, piriformis, obturator internus and externus, and gemelli muscles. SYN: t. major [TA] . lesser t. [TA] a pyramidal process projecting from the medial and proximal part of the shaft of the femur at the line of junction of the shaft and the neck; it receives the insertion of the psoas major and iliacus (iliopsoas) muscles. SYN: t. minor [TA] , small t., trochantin. t. major [TA] SYN: greater t.. t. minor [TA] SYN: lesser t.. small t. SYN: lesser t.. t. tertius [TA] SYN: third t.. third t. [TA] an occasional process at the proximal end of the lateral lip of the linea aspera of the femur, about on a level with the lesser t., giving insertion to the greater part of the gluteus maximus muscle. SEE ALSO: gluteal tuberosity. SYN: t. tertius [TA] .

trochanterian, trochanteric (tro-kan-ter′e-an, -ter′ik)
Relating to a trochanter; especially the greater trochanter.

trochanterplasty (tro-kan′ter-plas-te)
Plastic surgery of the trochanters and neck of the femur. [trochanter + G. plastos, formed]

trochantin (tro-kan′tin)
SYN: lesser trochanter.

trochantinian (tro-kan-tin′e-an)
Relating to the trochanter minor.

troche (trok, tro′ke)
A small, disk-shaped or rhombic body composed of solidifying paste containing an astringent, antiseptic, or demulcent drug, used for local treatment of the mouth or throat, the t. being held in the mouth until dissolved. The vehicle or base of the t. is usually sugar, made adhesive by admixture with acacia or tragacanth, fruit paste, made from black or red currants, confection of rose, or balsam of tolu. SYN: lozenge, morsulus, pastil (2) , pastille, trochiscus. [L. trochiscus fr. G. trochiskos, a little wheel, fr. trochos, a wheel]

trochiscus (troch) , pl .trochisci (tro-kis′kus)
SYN: troche. [L., fr. G. trochiskos, a small wheel, a lozenge, fr. trochos, a wheel]

trochlea, pl .trochleae (trok′le-a, -le-e) [TA]
1. A structure serving as a pulley. 2. A smooth articular surface of bone upon which another glides. [L. pulley, fr. G. trochileia, a pulley, fr. trecho, to run] t. femoris SYN: patellar surface of femur. fibular t. of calcaneus [TA] a projection from the lateral side of the calcaneus between the tendons of the peroneus longus and brevis. SYN: t. fibularis calcanei [TA] , peroneal t. of calcaneus&star, t. peronealis&star, peroneal pulley, processus trochlearis, spina peronealis, trochlear process. t. fibularis calcanei [TA] SYN: fibular t. of calcaneus. t. humeri [TA] SYN: t. of humerus. t. of humerus [TA] the grooved surface at the lower end of the humerus articulating with the trochlear notch of the ulna. SYN: t. humeri [TA] , pulley of humerus. muscular t. [TA] a fibrous loop through which the tendon of a muscle passes; the intermediate tendon of the digastric and omohyoid muscles pass through such a t.. SYN: t. muscularis [TA] , muscular pulley. t. muscularis [TA] SYN: muscular t.. t. musculi obliqui superioris bulbi SYN: t. of superior oblique (muscle). peroneal t. of calcaneus fibular t. of calcaneus. t. peronealis fibular t. of calcaneus. trochleae of phalanges of hand and foot palmar or plantar aspect of the intercondylar groove of the heads of the phalanges that accommodate the long flexor tendons. SYN: t. phalangis (manus et pedis). t. phalangis (manus et pedis) SYN: trochleae of phalanges of hand and foot. t. of superior oblique (muscle) a fibrous loop in the orbit, near the nasal process of the frontal bone, through which passes the tendon of the superior oblique muscle of the eye. SYN: t. musculi obliqui superioris bulbi. t. tali [TA] SYN: t. of the talus. t. of the talus [TA] the rounded superior articular surface of the talus that articulates with the distal ends of the tibia and fibula. SYN: t. tali [TA] , pulley of talus.

trochlear (trok′le-ar)
1. Relating to a trochlea, especially the trochlea of the superior oblique muscle of the eye. SYN: trochlearis (1) . 2. SYN: trochleiform.

trochleariform (trok-le-ar′i-form)
SYN: trochleiform.

trochlearis (trok-le-a′ris)
1. SYN: trochlear (1) . 2. SYN: trochleiform. [L.]

trochleiform (trok′le-i-form)
Pulley-shaped. SYN: trochlear (2) , trochleariform, trochlearis (2) .


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