QS Study

The lungs are a pair of breathing organs located with the chest which remove carbon dioxide from and bring oxygen to the blood. They are located in the chest, either side of the mediastinum. They are covered by a thin tissue layer called the pleura. Their main function is to oxygenate the blood. Left Lung contains – Heart, Arch of the aorta, Thoracic aorta, and Oesophagus.

Medial surface of the left lung

The mediastinal surface of the left lung can be considered in terms of the lung root and surrounding surface characteristics. The left ventricle and aorta are the key structures creating the left outermost layer of the mediastinum. Aorta ascends at first, arches over the left lung root, and after that descends behind the lung root. This surface is divided into two parts:

1 ) Vertebral surface.

2) Mediastinal surface.

Fig: Medial Surface of Left Lung

(1) Vertebral surface –

It is related to the bodies of the thoracic vertebrae & intervening intervertebral discs, posterior intercostal vessels & splanchnic nerves.

(2) Mediastinal surface –

It is related to the anterior part of the medial surface.

Its relations are as follows:

(1) Hilum of the lung.

(2) Pulmonary ligament.

(3) Anterior & left surfaces of the left ventricle & left auricle.

(4) The anterior surface of a part of the right ventricle.

(5) Pulmonary trunk.

(6) Left phrenic nerve & pericardiophrenic vessels.

(7) Arch of the aorta.

(8) Nerves:

  • Left phrenic.
  • Inferior cervical cardiac branch of the left vagus.
  • Superior cervical cardiac branch of left sympathetic trunk.
  • Left vagus nerve.
  • Left recurrent laryngeal nerve.

(9) Veins:

  • Left brachiocephalic vein.
  • Left superior intercostal vein.

(10) Descending thoracic aorta.

(11) Oesophagus.

(12) Thoracic duct.

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