From: superior, middle, and inferior cervical ganglia
Vasomotor, not secretomotor
Arterial supply
Superior thyroid artery
Branch of external carotid artery
Divides into anterior and posterior branches
Anterior branch
Supplies anterior thyroid
Anastomoses with opposite anterior branch
Posterior branch
Supplies posterior thyroid
Anastomoses with inferior thyroid artery
Inferior thyroid artery
Branch thyrocervical trunk from subclavian artery
Supplies inferior pole of thyroid
Thyroid ima artery
Branch of aorta
Occurs in 10% of all people
Unpaired, on left of midline
Supplies isthmus
Venous drainage
Three pairs of thyroid veins
Superior thyroid vein
Drains superior region of thyroid
Tributary of internal jugular
Middle thyroid veins
Drain middle of gland
Tributaries of internal jugular
Inferior thyroid veins
Drain inferior region of thyroid
Tributaries of brachiocephalic vein
Lymphatic drainage
Lymphatic vessels run with arteries
Drain to capsular network of lymphatics
→ prelaryngeal, pretracheal, or paratracheal nodes
→ deep cervical nodes
Innervation: sympathetic from cervical sympathetic gangliaParathyroid Gland
Small, oval endocrine glands
On medial half of posterior surface of lateral lobes of thyroid, external to capsule
Two pairs of glands
Superior glands slightly above entrance of inferior thyroid arteries
Inferior glands slightly below entrance of inferior thyroid arteries
Arterial supply
Superior thyroid artery
Inferior thyroid artery
Thyroid ima artery
Venous drainage
Parathyroid veins
→ thyroid plexus of veins
Lymph drainage: paratracheal and deep cervical lymph nodes