The trachealis muscle is a sheet of smooth muscle in the

trachea The trachea, also known as the windpipe, is a cartilaginous tube that connects the larynx to the bronchi of the lungs, allowing the passage of air, and so is present in almost all air- breathing animals with lungs. The trachea extends from the ...

Structure

The trachealis muscle lies posterior to the

and anterior to the

oesophagus The esophagus (American English) or oesophagus (British English; both ), non-technically known also as the food pipe or gullet, is an organ in vertebrates through which food passes, aided by peristaltic contractions, from the pharynx to th ...

. It bridges the gap between the free ends of C-shaped rings of cartilage at the posterior border of the

, adjacent to the

. This completes the ring of cartilages of the trachea. The trachealis muscle also supports a thin cartilage on the inside of the trachea. It is the only smooth muscle present in the trachea.

Function

The primary function of the trachealis muscle is to constrict the trachea, allowing air to be expelled with more force, such as during

cough A cough is a sudden expulsion of air through the large breathing passages that can help clear them of fluids, irritants, foreign particles and microbes. As a protective reflex, coughing can be repetitive with the cough reflex following three ph ...

ing.

Clinical significance

Tracheomalacia Tracheomalacia is a condition or incident where the cartilage that keeps the airway (trachea) open is soft such that the trachea partly collapses especially during increased airflow. This condition is most commonly seen in infants and young child ...

may involve

hypotonia Hypotonia is a state of low muscle tone (the amount of tension or resistance to stretch in a muscle), often involving reduced muscle strength. Hypotonia is not a specific medical disorder, but a potential manifestation of many different diseases ...

of the trachealis muscle. The trachealis muscle may become stiffer during ageing, which makes the whole trachea less elastic. In

infants An infant or baby is the very young offspring of human beings. ''Infant'' (from the Latin word ''infans'', meaning 'unable to speak' or 'speechless') is a formal or specialised synonym for the common term ''baby''. The terms may also be used to ...

, the insertion of an oesophagogastroduodenoscope into the oesophagus may compress the trachealis muscle, and narrow the trachea. This can result in reduced airflow to the lungs. Infants may be intubated to make sure that the trachea is fixed open.

References

{{Authority control Respiratory system Respiration

Structure

Function

Clinical significance

See also

References