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JAMA. 1899;XXXIII(22):1313-1320. doi:10.1001/jama.1899.92450740001001.
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The thyroid gland is an outgrowth from the hypoblastic layer of the embryo forming a tube lined by epithelium, derived from the ventral buccopharyngeal wall. It consists originally of three parts, a central and two lateral portions, the mesial portion being formed by a diverticulum arising from the vicinity of the second branchial arch, while the lateral lobes are developed as diverticulæ on either side from the posterior portion of the fourth branchial arch connected with the fourth branchial cleft. The tongue—according to His—has its origin in two separate portions, an anterior and a posterior part, the former consisting of the point and body originating in the tuberculum impar situated in the floor of the mouth; the latter portion or base coming from two masses situated in close proximity to the second and third branchial arches. In due time the two separate parts meet along a V-shaped fold, and at


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