Editing Thyroid (section)

== '''Gross anatomy''' ==

* Reddish-brown in colour
* Rubbery in texture
* Two lobes connected by an isthmus 2-3mm thick
* Typical weight 20g, which is mostly made up from the right and left thyroid lobes. Each lobe has a narrow upper pole and a broader lower pole.
* 4-6cm in height, and 1.3-1.8cm in both transverse and A-P dimensions
* Resembles the silhouette of a butterfly in the A-P plane, with two lateral lobes connected by an isthmus draped over the upper trachea just caudal to the cricoid cartilage
* 50-65% of people have a pyramidal lobe - extending superiorly from the isthmus, representing the caudal remnant of the thyroglossal duct
* There is a small posterolateral pyramidal projection/bump called the '''tubercle of Zuckerkandl'''
** A thickening from where the part from the lateral thyroid precursor (ultimobranchial body origin) fuses to the part from the median thyroid precursor (pharynx)
** Intimately associated with RLN in many cases
* Surrounded by a fibrous capsule, which also forms separate 'pseudolobules' within the parenchyma itself
* The fibrous capsule also coalesces into a solid ligamentous structure at the posterolateral aspect of the upper trachea called the '''suspensory ligament of Berry''' (lateral ligaments of the thyroid gland), which is attached to the cricoid cartilage
* Avascular space of Reeves - medial to upper pole, between upper pole of thyroid, and cricothyroid muscle