১.
The vertebral level where trachea begins
ব্যাখ্যা
The trachea is a tube composed of 16 to 20 U-shaped hyaline cartilages and the trachealis muscle. The trachea begins just inferior to the cricoid cartilage (C6 vertebral level) and ends at the sternal angle (T4 vertebral level), where it bifurcates into the right main bronchus and the left main bronchus. At the bifurcation of the trachea, the last tracheal cartilage forms the carina, which can be observed by bronchoscopy as a raised ridge of tissue in the sagittal plane.