The gland develops from the 1st gill pocket , behind the unpaired rudiment of the tongue, so that embryologically it represents part of the digestive canal. Foramen caecum indicates the location of the outgrowth of the gland. The epithelial cord growing from here in its upper part, before dividing it into two lobes, is converted into a lumen (ductus thyroglossus). At the end of the 4th week he usually atrophies and disappears, only foramen caecum in his tongue remains from him . The pyramidal lobe mentioned above represents the remainder of the ductus thyroglossus. Additional thyroid glands may also occur.  

Vessels (blood supply) of the thyroid gland.

The thyroid gland receives two upper thyroid arteries (from a. Carotis externa) , two lower (from truncus thyrocervicalis from a. Subclavia) and the fifth unpaired (inconstant) – a. thyroidea ima , which may depart from truncus brachiocephalicus , a. subclavia or from the aortic arch. The veins form plexuses located under the outer capsule; these plexuses flow into three veins on each side: vv. thyroideae superior, mediae et inferior (the first two pour in v. jugularis interna, the lower flows into v. brachiocephalica sinistra).       

Lymphatic vessels are numerous and form a rich plexus; a colloid is discharged along them; diverting lymphatic vessels go along the arteries and end in nodi lymphatici paratracheales, cervicales profundi et mediastinales.

Nerves (innervation) of the thyroid gland.

Nerves go from tr. sympathicus (mainly from the middle cervical node, partly from the upper or lower), from n. vagus (via nn. laryngei superior et inferior) and, possibly, from n. glossopharyngeus.