Editing Thyroid (section)

===Blood, lymph and nerve supply===
The thyroid is supplied with arterial blood from the [[superior thyroid artery]], a branch of the [[external carotid artery]], and the [[inferior thyroid artery]], a branch of the [[thyrocervical trunk]], and sometimes by an [[Human variability|anatomical variant]] the [[thyroid ima artery]],{{sfn|Gray's Anatomy|2008|pp=462–4}} which has a variable origin.{{sfn|Elsevier's|2007|p=343}} The superior thyroid artery splits into anterior and posterior branches supplying the thyroid, and the inferior thyroid artery splits into superior and inferior branches.{{sfn|Gray's Anatomy|2008|pp=462–4}} The superior and inferior thyroid arteries join behind the outer part of the thyroid lobes.{{sfn|Elsevier's|2007|p=343}} The venous blood is drained via [[superior thyroid vein|superior]] and [[middle thyroid vein]]s, which drain to the [[internal jugular vein]], and via the [[inferior thyroid veins]]. The inferior thyroid veins originate in a network of veins and drain into the left and right [[brachiocephalic vein]]s.{{sfn|Gray's Anatomy|2008|pp=462–4}} Both arteries and veins form a plexus between the two layers of the capsule of the thyroid gland.{{sfn|Elsevier's|2007|p=343}}

[[Lymph]]atic drainage frequently passes the [[prelaryngeal lymph nodes]] (located just above the isthmus) and the [[pretracheal lymph nodes|pretracheal]] and [[paratracheal lymph nodes]].{{sfn|Gray's Anatomy|2008|pp=462–4}} The gland receives [[sympathetic nervous system|sympathetic nerve]] supply from the superior, middle and inferior cervical ganglion of the [[sympathetic trunk]].{{sfn|Gray's Anatomy|2008|pp=462–4}} The gland receives [[parasympathetic nerve]] supply from the [[superior laryngeal nerve]] and the [[recurrent laryngeal nerve]].{{sfn|Gray's Anatomy|2008|pp=462–4}}