Blood supply of Thyroid glands

Blood supply of thyroid glands

-2 sets of arteries -3 sets of veins

Superior thyroid vein

-accompanies superior thyroid artery -drains into internal jugular vein

inferior thyroid artery

-branch of thyrocervical trunk -runs upward/medially behind carotid sheath-reach posterior aspect of gland -gives off number of branches-ascending cervical, inferior laryngeal (accompanies recurrent laryngeal nerve to larynx) -Supplies mainly posterior/inferior aspect of gland -sends branches to parathyroid glands *as it passes medially behind thyroid gland, ITA becomes closely related to recurrent laryngeal nerve

inferior thyroid vein

-drain to brachiocephalic veins -sometimes unite into one channel which drains into left brachiocephalic vein

middle thyroid vein

-drains to internal jugular vein

superior thyroid artery

-gives off superior laryngeal artery (parallel to external laryngeal nerve) -reaches superior pole of thyroid gland -divides into anterior and posterior branches

Posterior branch of superior thyroid artery

-passes to posterior side -may anastomose with branches of inferior thyroid artery

Thyroid ima artery

-present in ~3-10% of population -arises from brachiocephalic trunk/arch of aorta -ascends on anterior surface of trachea to supply thyroid gland

Thyroid veins

-superior -middle -inferior

anterior branch of superior thyroid artery

-supplies anterior/superior surfaces of thyroid gland -anastomoses with counterpart from opposite side