Human Anatomy, Part 1 - K. A. Dyubenko, A. K. Kolomiytsev, Yu. B. Chaykovsky 2002

Special Section
Respiratory System, systema respiratorium [respiratory apparatus, apparatus respiratorius] – General Overview
Topography of the Trachea

The Trachea extends from the upper border of the VII cervical vertebra to the IV–VII thoracic vertebrae. In individuals with a narrow chest, the tracheal bifurcation is located at the level of the IV–V thoracic vertebra, whereas in people with a broad chest, it lies at the level of the VI–VII vertebra.

The anterior surface of the cervical part of the trachea is related to the isthmus of The Thyroid Gland, the sternohyoid, and sternothyroid Muscles; the posterior surface is related to the Esophagus; and the lateral surfaces are related to the lobes of the thyroid gland and the neurovascular bundles of the neck.

The anterior surface of the thoracic part is related to the remnants of the Thymus and the aortic arch; the posterior surface is related to the esophagus and Pericardium; the right lateral surface is related to the azygos vein, right Vagus nerve, and Lymph Nodes; and the left lateral surface is related to the aortic arch, left recurrent laryngeal nerve, and lymph nodes.

The framework of the tracheal wall is formed by 16–20 hyaline tracheal cartilages, cartilagines tracheales, which are shaped as incomplete rings. The cartilages are connected by annular ligaments, ligamenta annularia. The posterior wall of the trachea is referred to as the membranous wall, paries membranaceus. It consists of smooth Muscle and Connective Tissue. The muscle fibers are oriented primarily circularly and partly longitudinally, forming the trachealis muscle, musculus trachealis. It mediates active Changes in the tracheal diameter during Respiration and coughing.

The mucous membrane of the trachea is lined with pseudostratified ciliated columnar epithelium. The submucosa contains numerous tracheal glands, glandulae tracheales, and lymphoid nodules, noduli lymphatici tracheales. Externally, the trachea is covered by a connective tissue adventitia.

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Fig. 287. Trachea, trachea, and Bronchi, bronchi (anterior view) (after R. D. Sinelnikov)

In newborns, the trachea is relatively short, with its bifurcation located at the level of the III–IV thoracic vertebra. Tracheal growth is very rapid During the first 6 months, slowing down subsequently until the age of 9–10 years. By 14–15 years of age, the length of the trachea doubles, and by 23–25 years, it triples.

Blood supply to the cervical part of the trachea is provided by the inferior thyroid Arteries, while the thoracic part is supplied by the internal thoracic, bronchial, and esophageal arteries. Venous drainage flows into the inferior thyroid, azygos, and hemiazygos Veins.

Lymph from the trachea drains into the paratracheal and tracheobronchial lymph nodes.

Innervation of the trachea is provided by fibers from the vagus nerve and the Sympathetic trunk.