Those go into ducts between the lobes of the gland (called interlobar or excretory ducts).

The dividing cellular cords of the tubular duct become the isthmus and lateral lobes of the gland to complete the formation of the rest of the gland.

TOTAL THYROIDECTOMY: This procedure is advocated because of the high incidence of multicentric involvement of both lobes of the gland and the possibility of dedifferentiation of any residual tumor to the anaplastic cell type.