Impressions on right lung mediastinal surface
In this specimen we can see the colored impressions on the mediastinal surface of right lung.
The impressions are caused by the following structures:
- Superior vena cava
- Inferior vena cava
- Cardiac impression (Right auricle, Right atria and ventricle)
- Arch of azygos vein
The Hilar structures visualized on the mediastinal surface:
Superior vena cava:
A large vein draining the upper part of the body. It is formed by the union of the right and left brachiocephalic veins. It is valveless and opens into the upper part of the right atrium.
Inferior vena cava:
A large vein draining the lower part of the body. It is formed by the union of the right and left common iliac veins. It opens into the right atrium and is guarded by the Eustachian valve.
Arch of azygos vein:
The azygos vein is a single vein (unpaired) present in the posterior mediastinum on the right side. It is formed by the union of the right ascending lumbar and right subcostal veins. It terminates by arching over the root of the right lung and finally drains into the superior vena cava. Its main tributaries are the right superior intercostal, posterior intercostal (5-11), hemiazygos and accessory hemiazygos veins.
The trachea (Latin, air vessel; also called the wind-pipe) is a 10-15 cm long tube situated in the lower part of the neck and superior mediastinum. Its upper under is continuous with the larynx at the level of C6 vertebra. It is made up of C-shaped cartilaginous rings (hyaline in nature and 16-20 in number) anteriorly. Posteriorly the gap is closed by a fibro-elastic membrane and contains trachealis muscle. At the level of the sternal angle (i,e, lower border of T4 vertebra) the trachea bifurcates into two principal bronchi.
The esophagus is a muscular tube which begins as a continuation of the pharynx at the level of C6 vertebra. Its course is divisible into three parts: cervical, thoracic and abdominal. It enters the abdominal cavity by passing through the esophageal opening of the diaphragm at the level of T8 vertebra and opens into the stomach. The esophagus presents a series of constrictions along its course. The constrictions are formed by the following structures: cricopharyngeus muscle (part of inferior constrictor of pharynx), arch of aorta, left bronchus, espophageal opening of the diaphragm.
The epartial bronchus or the upper lobe bronchus is the secondary bronchus of the upper lobe of the right lung. It arises above the level of the pulmonary artery
Pulmonary artery: The right and left pulmonary arteries arise as branches from the pulmonary trunk. The pulmonary trunk extends from the infundibulum of the right ventricle and conveys the deoxygenated blood to the lungs via the pulmonary arteries.
The hyparterial bronchus is a secondary bronchus that arises below the level of the pulmonary artery.
Pulmonary veins: They are four in number (two superior and two inferior). They carry oxygenated