| thyroid axis | A short arterial trunk arising from the subclavian artery, giving rise to the suprascapular (which may instead arise directly from the subclavian artery) and terminating by dividing into the ascending cervical and inferior thyroid arteries. Synonym: truncus thyrocervicalis, thyroid axis. (05 Mar 2000) |
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| thyroid binding globulin | <protein> Thyroid binding globulin (TBG) is a plasma protein which binds the majority of thyroid hormone in the bloodstream. Bound thyroid hormone is inactive, only the unbound fraction (0.3%) is considered active. Birth control pills and pregnancy can lead to increased TBG levels in the plasma. Androgens can decrease TBG levels in the plasma. (27 Sep 1997) |
| thyroid body | A butterfly-shaped endocrine gland in the neck that is found on both sides of the trachea windpipe). It secretes the hormone thyroxine which controls the rate of metabolism. (27 Sep 1997) |
| thyroid bruit | Vascular murmur heard over hyperactive thyroid gland, due to increased blood flow. (05 Mar 2000) |
| thyroid calcifications | <radiology> Miliary calcification, psammoma bodies, papillary thyroid carcinoma, extensive calcification, nodular goiter (12 Dec 1998) |
| thyroid cancer | <oncology> A form of cancer that can occur in all age groups, particularly those who have had exposure to radiation. Papillary carcinoma is the most common form of thyroid malignancy and usually affects women of child-bearing age. Symptoms include neck swelling, goitre, horse voice, cough, haemoptysis, diarrhoea and constipation. Follicular carcinoma occurs with increased frequency in those who have had radiation exposure to the neck. Other risk factors include a family history of thyroid disease and history for goitre. Follicular carcinoma constitutes about 30% of all thyroid cancers. It has a greater rate of recurrence and metastasis than that of papillary carcinoma (the most common form of thyroid cancer). Symptoms include enlargement of the thyroid gland or neck swelling, change in voice, cough (occasionally bloody) and diarrhoea. Papillary carcinoma is the most common thyroid cancer and usually affects women of child-bearing age. Incidence: approximately in 1 in 1,000. (02 Jan 1998) |
| thyroid carcinoma | <radiology> Papillary-follicular (75%), well-differentiated, 95% 5-yr survival with treatment, papillary may lead to neck nodes, follicular may lead to lungs, bone (haematogenous), anaplastic (20%), older patients, prognosis poor, medullary (5%), C cells, associated with pheochromocytoma (MEN-2 and MEN-3) see also: hot and cold nodules on radionuclide studies, risk factors (12 Dec 1998) |
| thyroid carcinoma risk factors | <radiology> Increased risk of malignancy: young female, male, history of radiation to head or neck, hard lesion, other neck masses, no shrinkage on TSH, family hx of thyroid carcinoma see: thyroid carcinoma (12 Dec 1998) |
| thyroid cartilage | The largest cartilage of the larynx consisting of two laminae fusing anteriorly at an acute angle in the midline of the neck. The point of fusion forms a subcutaneous projection known as the adam's apple. (12 Dec 1998) |
| thyroid colloid | The semifluid material that occupies the lumen of thyroid follicles; it contains thyroglobulin mainly. (05 Mar 2000) |
| thyroid crisis | Sudden and dangerous increase of the symptoms of thyrotoxicosis. (12 Dec 1998) |
| thyroid diverticulum | Thyroglossal diverticulum, the endodermal bud from the floor of the embryonic pharynx; the primordium of the parenchyma of the thyroid gland. (05 Mar 2000) |
| thyroid eminence | The projection on the anterior portion of the neck formed by the thyroid cartilage of the larynx; serves as an external indication of the level of the fifth cervical vertebra. Synonym: prominentia laryngea, Adam's apple, protuberantia laryngea, thyroid eminence. (05 Mar 2000) |
| thyroid foramen | An opening occasionally existing in one or both of the plates of the thyroid cartilage. Synonym: foramen thyroideum. (05 Mar 2000) |
| thyroid gland | A butterfly-shaped endocrine gland in the neck that is found on both sides of the trachea windpipe). It secretes the hormone thyroxine which controls the rate of metabolism. (27 Sep 1997) |