- The thyroid is supplied with arterial blood from the superior thyroid artery, and the inferior thyroid artery, a branch of the thyrocervical trunk, and sometimes by thyroid ima artery, which has a variable origin.
- The venous blood is drained by superior and middle thyroid veins, which drain to the internal jugular vein, and via the inferior thyroid veins drain into the left and right brachiocephalic veins.
- Lymphatic drainage frequently passes to the prelaryngeal lymph nodes (located just above the isthmus), and the pretracheal and paratracheal lymph nodes.