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Medical Dictionary


thyroglossal (thi-ro-glos′al)
Relating to the thyroid gland and the tongue, denoting especially an embryologic duct. SYN: thyrolingual.

thyrohyal (thi-ro-hi′al)
The greater cornu of the hyoid bone.

thyrohyoid (thi-ro-hi′oyd)
Relating to the thyroid cartilage and the hyoid bone. See t. (muscle).

thyroid (thi′royd)
1. Resembling a shield; denoting a gland (t. gland) and a cartilage of the larynx (t. cartilage) having such a shape. 2. The cleaned, dried, and powdered t. gland obtained from one of the domesticated animals used for food and containing 0.17–0.23% of iodine; formerly widely used in the treatment of hypothyroidism, cretinism, and myxedema, in certain cases of obesity, and in skin disorders. [G. thyreoeides, fr. thyreos, an oblong shield, + eidos, form] accessory t. SYN: accessory t. gland.

thyroidea (thi-roy′de-a)
SYN: thyroid gland. t. accessoria, t. ima SYN: accessory thyroid gland.

thyroidectomy (thi-roy-dek′to-me)
Removal of the thyroid gland. [thyroid + G. ektome, excision] “chemical” t. jargon for the reduction of thyroid function produced by the administration of antithyroid drugs. SEE ALSO: radiothyroidectomy. near-total t. removal of nearly all of each thyroid lobe leaving unresected only a small portion of gland adjacent to the entrance of the recurrent laryngeal nerve into the larynx. subtotal t. removal of at least one thyroid lobe and up to a near-total t..

thyroidism (thi′roy-dizm)
Obsolete designation for: 1. SYN: hyperthyroidism. 2. Poisoning by overdoses of a thyroid extract.

thyroiditis (thi-roy-di′tis)
Inflammation of the thyroid gland. SYN: thyroadenitis. [thyroid + G. -itis, inflammation] autoimmune t. SYN: Hashimoto t.. chronic atrophic t. replacement of the thyroid gland by fibrous tissue, the commonest cause of myxedema in older persons. chronic fibrous t. SYN: Riedel t.. chronic lymphadenoid t. SYN: Hashimoto t.. chronic lymphocytic t. SYN: Hashimoto t.. de Quervain t. SYN: subacute granulomatous t.. focal lymphocytic t. focal infiltration of the thyroid by lymphocytes and plasma cells. SEE ALSO: Hashimoto t.. giant cell t. SYN: subacute granulomatous t.. giant follicular t. a variant of Hashimoto t. in which lymphocytic infiltrate in thyroid has formed into giant follicles. Hashimoto t. diffuse infiltration of the thyroid gland with lymphocytes, resulting in diffuse goiter, progressive destruction of the parenchyma and hypothyroidism. SYN: autoimmune t., chronic lymphadenoid t., chronic lymphocytic t., Hashimoto disease, Hashimoto struma, lymphocytic t., struma lymphomatosa. ligneous t. SYN: Riedel t.. lymphocytic t. SYN: Hashimoto t.. parasitic t. chronic South American trypanosomiasis with involvement of the thyroid gland, causing myxedema. Riedel t. a rare fibrous induration of the thyroid gland, with adhesion to adjacent structures, which may cause tracheal compression. SYN: chronic fibrous t., ligneous struma, ligneous t., Riedel disease, Riedel struma. subacute granulomatous t. t. with round cell (usually lymphocytes) infiltration, destruction of thyroid cells, epithelial giant cell proliferation, and evidence of regeneration; thought by some to be a reflection of a systemic infection and not an example of true chronic t.. SYN: de Quervain t., giant cell t.. subacute lymphocyte t. a subacute variant of Hashimoto t..

thyroidology (thi-roy-dol′o-je)
The study of the thyroid gland, both normal and pathologic. [thyroid + G. logos, study]

thyroidotomy (thi′roy-dot′o-me)
SYN: laryngofissure. [thyroid + G. tome, incision]

SYN: hyperthyroidism.

thyrolaryngeal (thi′ro-la-rin′je-al)
Relating to the thyroid gland or cartilage and the larynx.

thyroliberin (thi-ro-lib′er-in)
A tripeptide hormone from the hypothalamus, which stimulates the anterior lobe of the hypophysis to release thyrotropin; l-pyroglutamyl-l-histidyl-l-prolinamide. SYN: thyroid-stimulating hormone-releasing factor, thyrotropin-releasing hormone. [thyrotropin + L. libero, to free, + -in]

thyrolingual (thi′ro-ling′gwal)
SYN: thyroglossal. [thyro- + L. lingua, tongue]

thyrolytic (thi-ro-lit′ik)
Causing destruction of thyroid gland cells. [thyro- + G. lytikos, dissolving]

thyromegaly (thi-ro-meg′a-le)
Enlargement of the thyroid gland. [thyro- + G. megas, large]

thyronine (thi′ro-nen, -nin)
An amino acid with a diphenyl ether group in the side chain; occurs in proteins only in the form of iodinated derivatives (iodothyronines), such as thyroxine.

thyropalatine (thi-ro-pal′a-tin)
Denoting the palatopharyngeus muscle.

thyroparathyroidectomy (thi′ro-par-a-thi′roy-dek′to-me)
Excision of thyroid and parathyroid glands.

thyropathy (thi-rop′a-the)
A disorder of the thyroid gland. [thyro- + G. pathos, suffering]

thyroperoxidase (thi-ro-per-oks′i-das)
A protein that participates in iodine metabolism in the thyroid follicle or in the follicular space; it utilized H2O2 to produce I+.

thyropharyngeal (thi-ro-fa-rin′je-al)
Denoting the t. portion of the inferior pharyngeal constrictor muscle.

A surgical method of restoring vocal quality by altering the geometry of the thyroid cartilage. [thyro- + G. plastos, formed]

thyroprival (thi-ro-pri′val)
Relating to thyroprivia, denoting hypothyroidism produced by disease or thyroidectomy. SYN: thyroprivic, thyroprivous. [thyro- + L. privus, deprived of]

thyroprivia (thi-ro-priv′e-a)
A state characterized by reduced activity of the thyroid.

thyroprivic, thyroprivous (thi-ro-priv′ik, -priv′us)
SYN: thyroprival.

thyroprotein (thi-ro-pro′ten)
1. SYN: thyroglobulin (1) . 2. An iodinated protein, usually casein, that has thyroxine activity.

thyroptosis (thi-rop-to′sis)
Downward dislocation of the thyroid gland. [thyro- + G. ptosis, a falling]

thyrotomy (thi′rot′o-me)
1. Any cutting operation on the thyroid gland. 2. SYN: laryngofissure. [thyro- + G. tome, a cutting]

thyrotoxic (thi-ro-tok′sik)
Denoting thyrotoxicosis.

thyrotoxicosis (thi′ro-tok-si-ko′sis)
The state produced by excessive quantities of endogenous or exogenous thyroid hormone. [thyro- + G. toxikon, poison, + -osis, condition] apathetic t. chronic t., presenting as cardiac disease or as a wasting syndrome, with weakness of proximal muscles and depression but with few of the more typical clinical manifestations of t.. t. medicamentosa a hyperthyroid state resulting from excessive doses of thyroid hormone preparation.

thyrotoxin (thi-ro-tok′sin)
1. A hypothetical substance formerly believed to be an abnormal product of diffusely hyperplastic thyroid glands in persons with Graves disease, and presumed to be the cause of the distinctive signs and symptoms of that condition (in contrast to simple hyperthyroidism). 2. A complement-fixing antigenic factor associated with certain diseases of the thyroid gland. 3. Rarely used term referring to any material toxic to thyroidal tissue.

thyrotroph (thi′ro-trof)
A cell in the anterior lobe of the pituitary that produces thyrotropin.

thyrotrophic (thi-ro-trof′ik)
SYN: thyrotropic. [thyro- + G. trophe, nourishment]

thyrotrophin (thi-rot′ro-fin, thi-ro-tro′fin)
SYN: thyrotropin.

thyrotropic (thi-ro-trop′ik)
Stimulating or nurturing the thyroid gland. SYN: thyrotrophic. [thyro- + G. trope, a turning]

thyrotropin (thi-rot′ro-pin, thi-ro-tro′pin)
A glycoprotein hormone produced by the anterior lobe of the hypophysis that stimulates the growth and function of the thyroid gland; it also is used as a diagnostic test to differentiate primary and secondary hypothyroidism. SYN: thyroid-stimulating hormone, thyrotrophin, thyrotropic hormone. [for thyrotrophin, fr. thyro- + G. throphe, nourishment; corrupted to -tropin, and reanalyzed as fr. G. trope, a turning]

thyroxine (T4) , thyroxin (thi-rok′sen, -sin)
The l-isomer is the active iodine compound existing normally in the thyroid gland and extracted therefrom in crystalline form for therapeutic use; also prepared synthetically; used for the relief of hypothyroidism, cretinism, and myxedema. labeled t. SYN: radioactive t.. radioactive t. t. in which a radioisotope of iodine (125I or 131I) is incorporated into its molecule; used in experiments tracing the metabolism of t.. SYN: labeled t., radiolabeled t., radiothyroxin. radiolabeled t. SYN: radioactive t.. t. sodium a preparation obtained by the action of a limited amount of sodium carbonate upon t.; it contains between 61 and 65% of iodine. See sodium levothyroxine, sodium liothyronine.

Thysanosoma actinoides (this-a-no-so′ma ak-ti-noyd′ez)
Fringed tapeworm of sheep, a relatively short, thick worm (family Anocephalidae) in which the posterior borders of the proglottids are fringed. It inhabits the small intestine, but often invades the bile ducts and causes many livers to be condemned for human food. It is essentially nonpathogenic and is common in stock-raising countries, where it infects a wide variety of ruminants; oribatid mites are probably the vectors.

The delay time between the inverting pulse and the “read” pulse in the inversion recovery experiment, in magnetic resonance imaging.

Symbol for titanium.

Abbreviation for transient ischemic attack.

tibia, gen. and pl. tibiae (tib′e-a, tib′e-e) [TA]
The medial and larger of the two bones of the leg, articulating with the femur, fibula, and talus. SYN: shin bone. [L. the large shinbone] saber t. deformity of the t. occurring in tertiary syphilis or yaws, the bone having a marked forward convexity as a result of the formation of gummas and periostitis. t. valga SYN: genu valgum. t. vara SYN: genu varum.

tibiad (tib′e-ad)
In a direction toward the tibia. [tibia + L. ad, to]

tibial (tib′e-al) [TA]
Relating to the tibia or to any structure named from it; also denoting the medial or t. aspect of the lower limb. SYN: tibialis [TA] . [L. tibialis]

tibiale posticum (tib-e-a′le pos-ti′kum)
SYN: os tibiale posterius.

tibialis (tib-e-a′lis) [TA]
SYN: tibial. [L.]

The tibia. [L. tibia, the shinbone]

tibiocalcanean (tib′e-o-kal-ka′ne-an)
Relating to the tibia and the calcaneus.

tibiofascialis (tib-e-o-fas-e-a′lis)
See entries under musculus t..

tibiofemoral (tib-e-o-fem′o-ral)
Relating to the tibia and the femur.

tibiofibular (tib-e-o-fib′u-lar)
Relating to both tibia and fibula; denotes especially the joints and ligaments between the two bones. SYN: peroneotibial, tibioperoneal.

tibionavicular (tib-e-o-na-vik′u-lar)
Relating to the tibia and the navicular bone of the tarsus. SYN: tibioscaphoid.

tibioperoneal (tib′e-o-per′o-ne′al)
SYN: tibiofibular.

tibioscaphoid (tib′e-o-skaf′oyd)
SYN: tibionavicular.

tibiotarsal (tib-e-o-tar′sal)
Relating to the tarsal bones and the tibia. SYN: tarsotibial.

tic (tik)
Habitual, repeated contraction of certain muscles, resulting in stereotyped individualized actions that can be voluntarily suppressed for only brief periods, e.g., clearing the throat, sniffing, pursing the lips, excessive blinking; especially prominent when the person is under stress; there is no known pathologic substrate. SEE ALSO: spasm. SYN: Brissaud disease, habit chorea, habit spasm. [Fr.] convulsive t. SYN: facial t.. t. de pensée a rarely used term for the habit of involuntarily giving expression to any thought that comes to mind. [Fr. of thought] t. douloureux SYN: trigeminal neuralgia. [Fr. painful] facial t. involuntary twitching of the facial muscles, sometimes unilateral. SYN: Bell spasm, convulsive t., facial spasm, palmus (1) . glossopharyngeal t. SYN: glossopharyngeal neuralgia. habit t. a habitual repetition of some grimace, shrug of the shoulder, twisting or jerking of the head, or the like. local t. a t. of very limited extent, as the winking of an eye or a twitch of a finger. psychic t. a gesture or exclamation made under the influence of an irresistible morbid impulse. rotatory t. SYN: spasmodic torticollis. spasmodic t. a disorder in which sudden spasmodic coordinated movements of certain muscles or groups of physiologically related muscles occur at irregular intervals. SYN: Henoch chorea.

ticarcillin disodium (ti-kar-sil′in)
The disodium salt of 6-(α-carboxy-α-thien-3-ylacetamido)penicillanic acid; a bactericidal antibiotic useful in treating Pseudomonas aeruginosa infections and similar in effect to carbenicillin disodium.

tick (tik)
An acarine of the families Ixodidae (hard ticks) or Argasidae (soft ticks), which contain many bloodsucking species that are important pests of humans and domestic birds and mammals, and that probably exceed all other arthropods in the number and variety of disease agents that they transmit. Ticks are differentiated from the much smaller true mites by possession of an armed hypostome and a pair of tracheal spiracular openings located behind the basal segment of the third or fourth pair of walking legs; the larva (seed t.) has six legs, and after molting appears as an eight-limbed nymph. Some important ticks are Amblyomma americanum (Lone Star t.) and A. hebraeum (South African bont t.); Argas persicus (adobe, fowl, or Persian t.) and A. reflexus (pigeon t.); Boophilus (cattle ticks); Dermacentor albopictus (horse or winter t.), D. andersoni (Rocky Mountain spotted fever or wood t.), D. nitens (tropical horse t.), D. occidentalis (Pacific or wood t.), and D. variabilis (American dog t.); Haemaphysalis chordeilis (bird t.) and H. laporis-palustris (rabbit t.); Ixodes pacificus (California black-legged t.), I. pilosus (paralysis t.), I. ricinus (castor bean t.), and I. scapularis (black-legged or shoulder t.); Ornithodoros coriaceus (pajaroello t.) and O. moubata (African relapsing fever or tampan t.); and Rhipicephalus everti (African red t.), R. sanguineus (brown dog t.), and R. simus (black-pitted t.).

tickling (tik′ling)
Denoting a peculiar itching or tingling sensation caused by excitation of surface nerves, as of the skin by light stroking.

ticolubant (ti-kol′oo-bant)
A leukotriene B4 receptor antagonist used as an antipsoriatic.

Abbreviation for L. ter in die, three times a day.

tidal (ti′dal)
Relating to or resembling the tides, alternately rising and falling.

tide (tid)
An alternate rise and fall, ebb and flow, or an increase or a decrease. [A.S. tid, time] acid t. a temporary increase in the acidity of the urine occurring during fasting. SYN: acid wave. alkaline t. a period of urinary neutrality or even alkalinity after meals due to withdrawal of hydrogen ion for the purpose of secretion of the highly acid gastric juice. SYN: alkaline wave. fat t. an increase in the fat content of blood and lymph following a meal. red t. a natural phenomenon resulting from higher than normal concentrations of the microscopic algae Gymnodinium breve in seawater. [when the causative organism is extremely concentrated, sea water can have a reddish-brown color.]

Friedrich, German anatomist, 1781–1861. See T. gland, T. nerve.

Alexander, German surgeon, 1864–1927. See T. syndrome.

tiglate (tig′lat)
A salt or ester of tiglic acid.


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