A narrow median bridge that joins together the lower thirds of the two lateral (right and left) lobes of the thyroid gland and usually covers the second and the third tracheal rings; the thyroid isthmus is variable in presence and size, can change shape and size, and can encompass a cranially extending pyramid lobe (lobus pyramidalis or processus pyramidalis), remnant of the thyroglossal duct. [ MP:0013163 ]
Synonyms: thyroid isthmus isthmus glandulae thyroideae thyroid gland isthmus
Term information
- FMA:49178
- MA:0000727
- UMLS:C0229583 (ncithesaurus:Thyroid_Gland_Isthmus)
- Wikipedia:Thyroid_isthmus
- VHOG:0000739
- neuronames:2643
- SCTID:245539003
- EHDAA2:0002031
- NCIT:C32887
- EHDAA:5777
- EMAPA:18195
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In mammals and in some reptiles, the thyroid is composed of two lobes connected by an isthmus; in birds and amphibians, the thyroid consists of two isolated lobes. (...) Despite these morphological differences, the ontogeny of the thyroid follows the same pattern in all vertebrates (...).[well established][VHOG]
Term relations
- organ part
- endoderm-derived structure
- connects some lobe of thyroid gland
- part of some thyroid gland