«tasdiqlayman» Tabiiy fanlar fakulteti dekani K. Asqarov

Nearby structures[edit]
The trachea passes by many structures of the neck and chest (thorax) along its course.
In front of the upper trachea lies connective tissue and skin.^[2] Several other structures pass over or sit on the trachea; the jugular arch, which joins the two anterior jugular veins, sits in front of the upper part of the trachea. The sternohyoid and sternothyroid muscles stretch along its length. The thyroid gland also stretches across the upper trachea, with the isthmus overlying the second to fourth rings, and the lobes stretching to the level of the fifth or sixth cartilage.^[2] The blood vessels of the thyroid rest on the trachea next to the isthmus; superior thyroid arteries join just above it, and the inferior thyroid veins below it.^[2] In front of the lower trachea lies the manubrium of the sternum, the remnants of the thymus in adults. To the front left lie the large blood vessels the aortic arch and its branches the left common carotid artery and the brachiocephalic trunk; and the left brachiocephalic vein. The deep cardiac plexus and lymph nodes are also positioned in front of the lower trachea.^[2]
Behind the trachea, along its length, sits the oesophagus, followed by connective tissue and the vertebral column.^[2] To its sides run the carotid arteries and inferior thyroid arteries; and to its sides on its back surface run the recurrent laryngeal nerves in the upper trachea, and the vagus nerves in the lower trachea.^[2]
The trachealis muscle contracts during coughing, reducing the size of the lumen of the trachea.^[3]
Blood and lymphatic supply[edit]

The upper part of trachea receives and drains blood through the inferior thyroid arteries and veins;^[2] the lower trachea receives blood from bronchial arteries.^[3] Arteries that supply the trachea do so via small branches that supply the trachea from the sides. As the branches approach the wall of the trachea, they split into inferior and superior branches, which join with the branches of the arteries above and below; these then split into branches that supply the anterior and posterior parts of the trachea.^[3] The inferior thyroid arteries arise just below the isthmus of the thyroid, which sits atop the trachea. These arteries join (anastamoses) with ascending branches of the bronchial arteries, which are direct branches from the aorta, to supply blood to the trachea.^[2] The lymphatic vessels of the trachea drain into the pretracheal nodes that lie in front of the trachea, and paratracheal lymph nodes that lie beside it.^[2]