ABSTRACT
The adult thyroid gland weighs 10-20 g. It is nearly always asymmetric and it is usually larger in women than it is in men.
Anatomical relations of thyroid and parathyroid glands are shown in the diagram (2):
Thyroid development commences at day 24 as a midline thickening and then as an outpouching of the endodermal floor of the pharyngeal cavity, which then descends. The parathyroid glands are derived from the epithelium of the third and fourth pharyngeal pouches.
