The trachea is a mobile cartilaginous and membranous tube. It begins in the neck as a continuation of the larynx at the lower border of the cricoid cartilage at the level of the 6th cervical vertebra. It descends in the midline of the neck.
In the thorax, the trachea ends below at the carina by dividing into right and left principal bronchi at the level of the sternal angle (opposite the disc between the 4th and 5th thoracic vertebrae). During expiration, the bifurcation rises by about one vertebral level, and during deep inspiration may be lowered as far as the 6th thoracic vertebra.