Pronunciation: trā′kē-ă, -kē-ē
Definition: The air tube extending from the larynx into the thorax to the level of the fifth or sixth thoracic vertebra where it bifurcates into the right and left bronchi. The trachea is composed of 16–20 incomplete rings of hyaline cartilage connected by a membrane (anular ligament); posteriorly, the rings are deficient for one fifth to one third of their circumference, the interval forming the membranous wall being closed by a fibrous membrane containing smooth muscular fibers. Internally, the mucosa is composed of a pseudostratified ciliated columnar epithelium with mucous goblet cells; numerous small mixed mucous and serous glands occur, the ducts of which open to the surface of the epithelium.
[G. tracheia artēria, rough artery]