The larynx is divided into three subsites:
- supraglottis (vestibule): from the inlet (aryepiglottic folds) to the false cords.
- false vocal cords: mucosal surface of the laryngeal vestibule
- arytenoid cartilages
- epiglottis: Leaf shaped cartilage with suprahyoid (free margin) and infrahyoid (fixed) portions. Attached to the thyroid lamina via thyroepiglottic ligament.
- aryepiglotic folds: from arytenoid cartilage to the inferolateral margin of epiglottis
- glottis: gap between the vocal folds.
- true vocal cords
- anterior commissure
- posterior commissure
- subglottis
- from the inferior aspect of the the glottis to the first tracheal ring
- mucosal area is closely related to the inferior surface of cricoid cartilage
Blood supply:
- Above the vocal folds, superior laryngeal branch of the superior thyroid artery. This enters the piriform recess below the internallaryngeal nerve by piercing the thyrohyoid membrane.
- Lower half, is supplied by the inferior laryngeal branch of the inferior thyroid artery. It accompnies the recurrent laryngeal nerve beneath the inferior constrictor of the pharynx.
- Venous return is through superior laryngeal vein which empty into superior thyroid vein, and inferior laryngeal vein which empty into the inferior thyroid vein.
Lymph drainage:
Supra and infraglottic parts, accompay the superior and inferior thyroid vessels and drain to the upper and lower group of the deep cervical node. Some pass through the cricothyroid mmrbe and drain to the prelaryngeal and pretracheal node.
Nerve supply:
- all laryngeal muscle is supplied by recurrent laryngeal of vagus, except cricothyroid (external branch of superior laryngeal nerve)
- the recurrent laryngeal pass under the lower border of the inferior constrictor behind the cricothyrid joint. It divides into anterior and posterior branch at the level of the isthmus of the thyroid gland. It reach the lower part of the piriform recess and then penetrates the laryngeal wall
- sensation of the mucous membrane above the vocal fold is by internal branch of the superior laryngeal nerve. Below the fold is by recurrent laryngeal of vagus.