Pulmonary trunk

Pulmonary trunk [truncus pulmonalis (PNA); synonym: pulmonary artery (artery pulmonalis, BNA), blood vein of Galen] - artery that carries venous blood from the right ventricle to the lungs. The projection of the vessel to the chest wall in front: II intercostal space or III rib on the left of the sternum.
Pulmonary trunk begins in the pericardium cavity from the cone of the right ventricle. At first he lies on the front, and then to the left of the ascending aorta.
On the body level IV thoracic vertebra pulmonary trunk is divided into right and left pulmonary arteries going into the lungs (AA. pulmonales dext. et sin.) (see the Light).
Length HP 4-6 cm diameter 3-3,5 see HP are constantly on the existing small Vienna, environmental his mouth;
in this place to HP adjacent right and left tabs of the Atria, and back, and bottom - left atrium. At the beginning of the pulmonary trunk is valve - valva trunci pulmonalis preventing back-flow; blood during diastole.
The division angle HP more blunt, open up and to the right. From the trachea HP separated loose parabasal fiber, which is non cardiac nerve plexus. The length of the right pulmonary artery about 4 cm in diameter 2-2,5 cm, length of the left - 3.3 cm, diameter of 1.8 see the Right and left pulmonary arteries are divided into equity and segmental branches corresponding to the shares and segments of the lungs (Fig. 1).

Fig. 1. The ratio of the bronchi and branches of the pulmonary arteries (rear view): 1 - truncus pulmonalis; 2 - a. pulmonalis dext; 3 - a. pulmonalis sin.

Pulmonary trunk belongs to the elastic type arteries. In the middle shell distinguish it longitudinal and circular layers of smooth muscle fibers; its Foundation is a dense network of elastic fibers. At the beginning HP ring fibers form a kind of the sphincter.
The blood supply to the wall HP perform coronary and bronchial artery.
Innervation: wandering nerves, branches sympathetic trunks, phrenic nerves and fibres of cerebrospinal node CV-ThV.
Histology - see Artery.