Respiratory tract

Last revised by Dr Daniel MacManus on 26 Aug 2022

The respiratory tract refers to the portion of the respiratory system that conducts air into and out of the body. It is conventionally divided into upper and lower tracts.

The upper respiratory tract (URT), also known as the upper airways, is the collective term for the components of the respiratory system proximal to the trachea:

Some texts include the paranasal sinuses in the upper respiratory tract as they are in direct communication with the nasal cavity, lined by a thin layer of respiratory epithelium and play a role in humidification of the inspired air and phonation.

The lower respiratory tract (LRT), also known as the lower airways, is the collective term for the components of the respiratory system distal to the larynx:

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Cases and figures

  • Figure 1: upper respiratory tract on CT neck (annotated)
    Drag here to reorder.
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