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Also known as the windpipe.
A cartilaginous tube that connects the pharynx and larynx to the lungs, allowing the passage of air.
It extends from the larynx and branches into the two primary bronchi.
At the top of the trachea the cricoid cartilage attaches it to the larynx.
The cricoid cartilage is the only complete tracheal ring.
Other tracheal rings are incomplete rings of reinforcing cartilage.
The cartilaginous rings are incomplete to allow the trachea to collapse slightly so that food can pass down the esophagus.
The interior wall of the trachea is formed by 14 to 20 C shaped cartilaginous rings and the posterior wall is composed of the trachelis muscle.
The ends of the rings are joined by the trachealis muscle, which are joined vertically by bands of fibrous connective tissue, the annular ligaments of trachea.
The trachealis muscle contracts during coughing, reducing the size of the lumen of the trachea to increase the rate of air flow.
On inspiration the average adult tracheal length is 10 cm, with a normal anterior posterior diameter of 2. 2 to 2. 9 cm in men and 1. 9 to 2. 6 cm in women.
The transverse diameter ranges from 2. 7 to 3. 4 cm in men and from 2.2 to 2.6 cm in women.
The epiglottis closes the opening to the larynx when swallowing.
The trachea is lined with an epithelium that has goblet cells which produce protective mucins.
Intubation and tracheotomy is performed for ventilation when needed.
The adult trachea has an inner diameter of about 1.5 to 2 centimetres (0.6 to 0.8 in) and a length of about 10 to 11 centimetres (4 in.).
The trachea begins at the bottom of the larynx, and ends at the carina, the point where the trachea branches into left and right main bronchi.
The trachea begins level with the sixth cervical vertebra .
The trachea ends on each side in an imperfect ring, which encloses the beginning of the bronchus.
The esophagus lies posteriorly to the trachea.
The flap-like epiglottis closes the opening to the larynx during swallowing to prevent swallowed matter from entering the trachea.
The sternohyoid and sternothyroid muscles and the thyroid lie on top of the upper part of the trachea
The thyroid gland lies below the cricoid cartilage.
The isthmus of the thyroid, which connects both wings of the thyroid, lies directly in front, whereas the wings lie on the front and stretch to the side.
The trachea is no more than 4mm diameter during the first year of life, expanding to its adult diameter by late childhood.
It is more mobile and of more variable length, deeper, and smaller in children.
It is lined with a layer of pseudostratified ciliated columnar epithelium, and contains goblet cells, which are glandular columnar epithelial cells that produce mucus.
Mucus moistens and protect the airways by trapping inhaled foreign particles that the cilia move upward toward the larynx and then the pharynx where it can be either swallowed into the stomach or expelled as phlegm.
Tracheal inflammation as well as that of the larynx and bronchi is known as croup, which often causes a distinct, barking cough.
Tracheal intubation refers to the insertion of a tube down the trachea to ensure a person receives enough oxygen when sedated.
When tracheal intubation is impossible, a tracheotomy is often performed to insert a tube for ventilation.
The opening via a tracheotomy is called a tracheostomy.
In an emergency situation, a cricothyrotomy can provide access to the trachea.
A tracheoesophageal fistula is a congenital defect in which the trachea and esophagus are abnormally connected.
Following laryngectomy a puncture hole is created between the esophagus and the trachea, restoring the ability to speak after the vocal cords have been removed.
Tracheal shaving of the cricoid cartilage can lessen the prominence of the Adam’s apple, and is often carried out in transgender surgery.