Practical pathology

by Aldred Scott Warthin

5. Section of the Lungs. The general inspection of the pleural cavities and pleural surfaces is made as soon as the thoracic cavity is opened, as indicated above. If a pneumothorax is present the pleural cavity on the affected side is filled with water, the neck organs are exposed and a tube inserted into the trachea. When air is forced through this bubbles will escape from the perforation and the opening can be easily located. When extensive or complete pleural adhesions are present, so that they cannot be separated, it becomes necessary to remove the costal pleura in connection with the visceral layer. This is accomplished by loosening the costal pleura and subpleural fascia at the cut edge of the ribs with the blade of the knife, until the fingers and, finally the hand, can be worked in between the costal pleura and the chest-wall, gradually separating the two until the entire lung is freed with both layers of pleura adherent. Firm adhesions at the apex may have to be cut with the knife. Similar adhesions with the pericardium or diaphragm may make it necessary to cut out the adherent portion with scissors or knife and remove it in connection with the lung. When the pleural adhesions are very firm upon the right side the prosector may find it most convenient to stand at the left side of the cadaver and from this position separate the right costal pleura from the chest wall. An assistant may be of great service in pulling the thoracic wall outward. The edge of the ribs or cartilages may be covered with a towel or the skin may be drawn over it to protect the hands. In extreme cases it may be necessary to saw the ribs and remove them in connection with the lungs. Sometimes the adhesions may be separated more easily if the neck-organs are first removed down to the clavicle, and then, in connection with the lungs, are removed en masse, by means of powerful tugs, from above downward. The apical and posterior adhesions may be torn fairly easily in this way when ordinary manipulations in the thoracic cavity have no effect upon them.

When the pleural surfaces are free the left lung is lifted out of the cavity onto the right edge of the chest-wall, pulling it forcibly over to the right so that its posterior surface becomes uppermost. In this position the lung may be sectioned by one or more main incisions made with the long section-knife, cutting the organ from apex to base, down upon the ribs in the direction of the main bronchi and vessels. After the examination of the cut surfaces the organ may be returned to the cavity. It is better, however, to remove the lung, and section it outside the body. This is done by cutting the mediastinal pleura, pulmonary vessels and main bronchus with the cartilage-knife, while the lung is held upon the right edge of the thoracic opening, holding the knife so that its blade strikes the edge of the costal cartilages.

Fig. 42.—Section of left lung. (After Nauwerck.)

The lung, when free, is placed upon the board with its hilus downward and base toward the prosector. (See Fig. [42].) It is then held in the left hand, as shown in the illustration, the thumb holding the lower lobe, the index-finger between the lobes with its tip upon the main bronchus, the other fingers holding the upper lobe. With the long section-knife held slightly obliquely toward the anterior edge the main-incision is now made in one sweeping cut from apex to base, along the line of greatest convexity, down upon the main-bronchus and its chief branches and the large vessels. Care should be taken not to cut off the bronchi of the two lobes from the main bronchus. Incisions parallel to the main one may be made, if desired. Usually it suffices to go carefully over the remaining part of the lung, feeling it carefully for airless solid areas; if such are present they may be sectioned separately. The bronchi are then opened from the cut surface by means of the probe-pointed scissors, cutting as near to the pleura as possible. The sound or director may be used with advantage in opening up cavities from the bronchi. The position of the lung should be so changed that the bronchi always extend away from the prosector in a straight line. The portion of the lung containing the uncut bronchus should be left hanging over the left hand to put it on the stretch, thereby facilitating greatly the opening of the bronchus. The pulmonary vessels are opened with fine probe-pointed scissors from the cut surface. The bronchial lymphglands are then sectioned with the knife.

Fig. 43.—Section of right lung. (After Nauwerck.)

The right lung is then lifted up out of the thorax onto the right side of the thoracic opening, and is either sectioned in this position, or the mediastinal pleura, pulmonary vessels and bronchus are cut from below upward with the knife, its edge being directed against the ribs. When freed the lung is placed on the board, root downward and apex toward the prosector. (See Fig. [43].) The index-finger is put between the upper and lower lobes, the thumb holds the upper lobe, the other fingers are spread out over the surface of the lower lobe. The main-incision is then made in a sweeping cut, from base to apex, along the line of greatest convexity, the knife-blade being held slightly obliquely toward the anterior border (see Fig. [43]), cutting down upon the main bronchus and its first division. Other parallel cuts may be made. The middle lobe is then sectioned by a sagittal incision on its anterior surface, directed toward its anterior border. The bronchi, pulmonary vessels and bronchial lymphnodes are then opened as in the case of the left lung.

Bacteriologic examinations may be made from smears or cultures made from the cut surfaces; or, to avoid contamination, the surface may be seared with a hot iron and the material obtained by means of a sterile pipette pushed through the seared surface into the lung-tissue.

The lungs may also be removed by drawing them downward and outward, away from the root, while the bronchi and pulmonary vessels are cut, the knife being directed against the vertebræ, care being taken to avoid cutting the aorta and œsophagus. The lungs are then lifted up toward the middle line, while the mediastinal pleuræ are cut. The section of the lungs may be carried out, if so desired, from the root, the main bronchus and then all of the branches as far as the pleuræ being opened up by means of the probe-pointed scissors. Other incisions may be made if desired.