The examinations of thyroid gland isthmus topography in foetal period development --practical importance

The studies aimed at following isthmus of thyroid position changes in particular months of its intrauterine development. Survey material consisted of 124 human foetus thyroids aged 4-7 months of intrauterine development. The basic examination method was classical anatomical preparation. Three aspects were considered in thyroid isthmus position assessment: holotopy, skeletotopy and syntopy. The gland holotopy analysis was carried out with the usage of isthmus position indices elaborated especially for the studies. The results were statistically analysed. Thyroid isthmus was observed to change its position. Although statistically significant differences in thyroid isthmus position were not proved, some tendencies of the one-position changes were detected, especially of larynx and trachea skeletons. The tendencies were based on a relatively more significant lowering of isthmus in comparison with gland lateral lobes. The basic reason for thyroid isthmus position changes in the development period is a disproportion between foetus gland and cervix growth rates.