The larynx is an inferior continuation of the oropharynx. It extends from the epiglottis (namely the glossoepiglottic and pharyngoepiglottic folds) to the inferior aspect of the cricoid cartilage. Inferiorly, it continues as the cervical trachea. The larynx also forms part of the upper respiratory tract.

supraglottis: extends from the tip of the epiglottis to the laryngeal ventricle
- epiglottis: divided into suprahyoid and infrahyoid portions
- pre-epiglottic space
- arytenoid cartilages
- aryepiglottic folds
- false vocal cords
- paraglottic space
glottis
subglottis: extends from the inferior surface of the true vocal cords to the inferior aspect of the cricoid cartilage

Relations

anterior: strap muscles, anterior jugular vein
posterior: esophagus, laryngopharynx
superior: hyoid bone, laryngopharynx
inferior: trachea

Arterial supply

above the vocal cords: superior laryngeal artery (branch of the superior thyroid artery)
below the vocal cords: inferior laryngeal artery (branch of the inferior thyroid artery)

Venous drainage

above the vocal cords: superior laryngeal vein accompanies its artery and drains into the superior thyroid vein (a tributary to the internal jugular vein)
below the vocal cords: inferior laryngeal vein accompanies its artery and drains into the inferior thyroid vein (a direct tributary to the brachiocephalic vein)

Lymphatic drainage

supraglottic: the supraglottic lymphatic network follows the superior laryngeal artery, piercing the thyrohyoid membrane and then draining into the superior deep cervical nodes and the pre-epiglottic nodes ⁶.
subglottic: the infraglottic lymphatic network drains to the inferior deep cervical nodes, following the inferior laryngeal artery, and/or the prelaryngeal (Delphian) nodes via the conus elasticus (aka the lateral cricothyroid ligaments) ⁶.

Both the superior and inferior deep cervical nodes then drain into the right and left jugular trunks, which subsequently empty into the right lymphatic duct and the thoracic duct on the left.

Innervation

motor: the recurrent laryngeal nerve supplies all the intrinsic muscles of the larynx apart from the cricothyroid muscle, which is supplied by the external laryngeal nerve
sensory:
- above the vocal cords (supraglottic): internal laryngeal nerve (branch of the superior laryngeal nerve)
- below the vocal cords (infraglottic): recurrent laryngeal nerve

Development

the larynx is formed from the laryngotracheal groove, which is related to the caudal aspect of the floor of the primordial pharynx
the cartilages of the larynx develop from the 4^th and 6^th pharyngeal arches