Fetal anatomy of parathyroid glands

The aim: To study the forms of anatomical variability of the external structure of the upper and lower parathyroid glands in the fetal period of human ontogenesis.

Materials and methods: The study involved 48 specimens of human fetuses with 81,0-375,0 mm of crown-rump length (CRL). The study was conducted by means of macromicroscopic preparation, morphometry and variation statistics method.

Results: The age and individual anatomical variability, complex way of development and formation of synotopic embryotropographic correlations of the upper and lower parathyroid glands in the prenatal period of human ontogenesis create numerous prerequisites for the emergence of variants of their external structure and topography in the fetuses of both different and the same age groups.

Conclusions: There is a significant anatomical variability of the upper and lower parathyroid glands in 4-10-month-old fetuses, which is manifested by varieties of their shape and topical location. Aplasia of the upper parathyroid glands, which was found in two human fetuses aged 7 months, was due to the fetures of their organogenesis and the formation of syntopy in the embryonic and prefetal periods of their development. Parathyroid glands are mainly supplied with blood by the branches of the inferior thyroid artery. The branches of the upper thyroid artery and the arteries of adjacent organs: larynx, trachea and esophagus are involved in the blood supply. The right and left inferior thyroid veins are tributaries of the corresponding brachiocephalic vein, paired (right and left) superior and middle thyroid veins are those for the internal jugular vein.