Details
Impressions on left lung mediastinal surface
In this specimen we can see the colored impressions on the mediastinal surface of the left lung.
The impressions are caused by the following structures:
- Left common carotid artery
- Cardiac impression of the left auricle and left ventricle
- Arch of aorta
- Descending aorta
- Left brachiocephalic vein
- Oesophagus
The Hilar structures seen on the mediastinal surface:
Common carotid artery:
It is a direct branch of the arch of aorta on the left side and arises from the brachiocephalic trunk on the right side. The right and left common carotid arteries supply the head and neck with oxygenated blood. The common carotid artery divides in the neck at the level of the upper border of thyroid cartilage to form the external (supplies the outer regions of head and neck) and internal carotid arteries (supplies the brain)
Arch of aorta:
The arch of aorta is the part of the aorta that distributes blood to the head and neck and upper extremities of the body via the brachiocephalic trunk, the left common carotid, and the left subclavian arteries.
Descending aorta:
The descending thoracic aorta begins as a continuation of the arch of aorta and is located in the posterior mediastinum. It extends from the lower border of the fourth thoracic vertebra at the level of the sternal angle to the lower border of the 12th thoracic vertebra. At its lower end it passes through the aortic opening of the diaphragm to become continuous with the abdominal aorta. The following are the branches of the descending thoracic aorta: pericardial, esophageal, mediastinal, left bronchial, posterior intercostal arteries (3rd to 11th spaces), subcostal, and superior phrenic arteries.
Brachiocephalic vein:
The brachiocephalic vein, also known as the innominate vein, is a paired vein of the superior mediastinum that drains the venous blood from the head and neck, upper limbs and the upper part of the thorax. The vein is formed by the union of the subclavian and internal jugular veins on both sides. The right and the left brachiocephalic veins then unite to form the superior vena cava.
Oesophagus:
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.
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.
Pulmonary veins:
Pulmonary veins: They are four in number (two superior and two inferior). They carry oxygenated
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