The trachea is the part of the respiratory tract that leads from the larynx and ends lower down in the thoracic cavity where it divides into the two main bronchi (left and right).
Location of the Trachea
The trachea starts where the larynx ends – at the level of the C6 vertebra – and run down the middle of the neck anterior to the esophagus. Tracheal deviation, where the trachea shifts from this middle position (media plan) indicates some disease of the respiratory system or thoracic cavity. The trachea ends around the level of the T4 to T5 vertebrae. The point where it terminates also correlates with the sternal angle – the junction of the manubrium and body of the sternum (breastbone).
Picture from Wikimedia Commons
Structure of the Trachea
The trachea is a fibrocartilaginous tube. It is lined with ciliated respiratory epithelium and has incomplete C-shaped tracheal rings to prevent the trachea from collapsing. The gaps between the two ends of the C-shaped rings, which lies at the posterior part of the trachea, are joined by the trachealis muscle. This makes the posterior part of the trachea flat compare to the rounder front (anterior) and sides (lateral).
Function of the Trachea
- The primary function of the trachea is to allow air to pass between the larynx and bronchi. It allows the air to be divided and routed into both lungs by terminating into the two main bronchi.
- The ciliated respiratory epithelium also traps dust particles in the air and propels it out of the respiratory passages, towards the pharynx (throat).
- The trachealis muscle that joins the two ends of the tracheal ring can contract thereby constricting the tracheal tube. This is useful for increasing the pressure during coughing to evacuate any irritants more effectively.