Question

In the scapular line - where does the pleural cavity end? Where does the lung end?

Answer 1

The pleural cavity ends at the level of the 12th rib in the scapular line.

The lung extends to the level of the 10th rib in the scapular line.

Step-by-step explanation:

The pleural cavity is the space between the visceral and parietal layers of the pleura, which surround the lungs. In the scapular line, the pleural cavity terminates at the level of the 12th rib. This means that below this rib, there is no space between the pleura, and the lung comes in direct contact with the chest wall.

The lung, on the other hand, extends slightly higher than the pleural cavity. In the scapular line, it reaches the level of the 10th rib. This implies that the lower part of the lung may extend beyond the confines of the pleural cavity, creating an area known as the costodiaphragmatic recess.

Understanding the termination points of the pleural cavity and the lungs is crucial in clinical contexts such as thoracentesis or lung examinations, as it helps healthcare professionals target specific areas for diagnostic or therapeutic procedures.

Answer 2

The pleural cavity ends slightly lower than where the lung tissue ends, with the lung typically extending to the 7th or 8th rib and the pleural cavity to the 10th rib in the scapular line.

Step-by-step explanation:

In the scapular line, the pleural cavity and lung margins are not identical. The pleural cavity extends slightly beyond the lungs, due to the presence of the pleural membranes. The lung tissue itself terminates at a somewhat higher level than the pleural cavity.

The visceral pleura is the layer covering the lungs and extending into lung fissures, whereas the parietal pleura is the outer layer lining the thoracic wall, mediastinum, and diaphragm. The space between these two layers is the pleural cavity, which contains pleural fluid. This fluid acts as a lubricant, allowing the lungs to move smoothly during respiration.

In relation to the scapular line on the back, the lower border of the lung typically extends to around the level of the 7th or 8th rib, while the pleural cavity extends slightly further down, reaching approximately the level of the 10th rib. This allows room for the lungs to expand during inhalation without touching the more rigid aspects of the thoracic cavity.