Mensuration - Inspection Of The Lungs

This consists in measurements of the chest. By means of mensuration the degree of mobility of the chest walls and the breathing capacity may be ascertained, also any departure from the natural symmetry caused by the. accumulation of fluid in one side, morbid growths, etc.

Succussion - Inspection Of The Lungs

Succussion is a shaking movement given to the chest for the purpose of detecting the presence of fluid. When air is also present in the pleural cavity, sounds will be produced by the splashing of the liquid serum or pus; if no air is present, no sounds will be heard, even though a considerable quantity of fluid may be contained in the chest.

Percussion - Inspection Of The Lungs

This is one of the most important of all means for examination of the chest. It consists in striking upon the chest-wall for the purpose of comparing the sounds produced by the percussion with sounds similarly produced in health. Percussion is best performed by placing the forefinger or middle finger of the left hand upon the chest, preferably in the space between the ribs, and striking it a quick elastic blow with the tips of the fingers of the other hand. The force of the blow should be sufficient to elicit a distinct sound. The sounds may be intensified by placing the patient so that his shoulders may rest against a door. Care should be taken to have both shoulders supported equally. The percussion should be performed upon the bare skin or with not more than a single thickness of muslin over the flesh. When performed outside the clothing, as we have often seen it done, nothing accurate can be learned of the state of the lungs. One side of the chest should be compared with the other. Sounds produced in this way differ chiefly in quality and pitch. The sound produced in health by striking the chest has a peculiar resonant quality called pulmonary resonance. It is never heard elsewhere. The pitch is low. When this sound is somewhat muffled, it is said to be dull. This condition naturally exists at the apex of the lung, above the clavicle, and below the fifth rib on the right side, over the liver. When the resonance is absent, the condition is known as flatness. This sound may be found in health over the kidneys and the lower part of the liver, near the seventh rib. Dullness is found in pneumonia and consumption, being produced by consolidation of the lung. Flatness is sometimes found in the same diseases and also in dropsy of the chest. Tympanitic resonance is another modification of sound which may be found over the stomach and bowels in health. It is noticed in cases in which one side of the chest has been filled with air, the lung itself having collapsed, a condition known as pneumo-thorax. It is also sometimes observed when large cavities have formed in the lungs. In cases in which cavities exist in the lungs, two other peculiar modifications are sometimes produced; viz., amphoric resonance, which is produced by a cavity possessing rigid walls, and the cracked-pot resonance, produced when the walls are flaccid. The first sound is like that produced by tapping upon a bottle The second is described by its name, the peculiarity being due to the coming together of the walls when percussion is performed. It is heard only when the patient's mouth is open and placed near to the ear of the examiner.

Percussion is sometimes practiced with an instrument called a pleximeter, consisting of a hammer and a small disk, the latter being placed upon the chest-wall and struck with the hammer. The fingers are much more efficient and accurate than any artificial means which has yet been devised.

Auscultation - Inspection Of The Lungs

Many of the most important indications respecting diseases of the chest are obtainable only by this means, which consists in listening at the chest wall by the ear alone, placed against the chest, or by the aid of an instrument known as the stethoscope, a cut of which is shown in Fig. 300.

Fig. 300. Stethoscope.

Fig. 300. Stethoscope.

In auscultation, attention is given to both inspiration and expiration. Each has its particular characteristics in health and in disease. In health, the inspiratory sound is of a peculiar breezy character, and low in pitch; the expiratory sound, if present, very short, and still lower in pitch. The sounds heard over the large bronchial tubes at the upper part of the sternum differ from this quite materially, resembling that produced by air drawn through a tube, being high in pitch, and the expiratory sound higher than the inspiratory, and continued longer.