| inferior thyroid tubercle | A slight lateral projection from the lower margin of the lamina of the thyroid cartilage on either side, at the inferior end of the oblique line. Synonym: tuberculum thyroideum inferius. (05 Mar 2000) |
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| inferior thyroid vein | <anatomy, vein> Unpaired vein formed by veins from the isthmus and lateral lobe of the thyroid gland and from the plexus thyroideus impar; it terminates in the left brachiocephalic vein. Synonym: vena thyroidea inferior, vena thyroidea ima. (05 Mar 2000) |
| infrahyoid branch of superior thyroid artery | <anatomy, artery> Small branch from the initial part of the superior thyroid artery coursing along the hyoid bone deep to the thyrohyoid muscle to anastomose with its contralateral partner. Synonym: ramus infrahyoideus arteriae thyroidea superioris. (05 Mar 2000) |
| isthmus of thyroid | The central part of the thyroid gland joining the two lateral lobes. Synonym: isthmus glandulae thyroideae. (05 Mar 2000) |
| oesophageal branches of the inferior thyroid artery | <anatomy, artery> Distribution: upper one-quarter of oesophagus; anastomosis: oesophageal branches of thoracic aorta. Synonym: rami oesophageales arteriae thyroideae inferioris. (05 Mar 2000) |
| ectopic thyroid | <radiology> Usually connects to normal thyroid, sites: lingual thyroid, thyroglossal duct remnant, anterior mediastinum (retrosternal thyroid), btw trachea and oesophagus, struma ovarii (teratoma variant), use pertechnetate first (rather than I-131) because of lower dose (12 Dec 1998) |
| thyroid | 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 acropachy | <radiology> Periosteal reaction, metacarpals, long bones of lower limbs, pretibial myxoedema, exophthalmos, prob secondary to long-standing exposure to LATS, 0.5 - 10% of patients after thyroidectomy for thyrotoxicosis (12 Dec 1998) |
| 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) |
| 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) |