trachea (anatomy)

Last reviewed 01/2018

The trachea is a central conducting airway between the larynx and principal bronchi. The division of the trachea into two principal bronchi at the tracheal bifurcation marks its inferior boundary. In the adult, it is 9-12cm long and 2-2.5cm wide. The tracheal wall is characterised by 15-20 regularly spaced tracheal cartilages which are deficient posteriorly.

The origin of the trachea is in the neck just inferior to the cricoid cartilage. This is the level of the C6 vertebra posteriorly. On average, the inferior margin of the trachea is the lower border of the manubrium sternii however, in full inspiration the elasticity of the trachea allows it to extend more inferiorly by 4-6cm.

The trachea can be divided into two continuous sections:

  • cervical section: the portion superior to the level of the thoracic inlet
  • thoracic section: from thoracic inlet inferiorly to level of its bifurcation