A medical handbook : for the use of practitioners and students / by R.S. Aitchison.

  • Aitchison, R. S. (Robert Swan)
Date:
1893
Catalogue details

Licence: Public Domain Mark

Credit: A medical handbook : for the use of practitioners and students / by R.S. Aitchison. Source: Wellcome Collection.

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    and others consider it to be produced by the vibration of the air particles entering the alveoli—i.e., by numerous stenosis murmurs. This might be expected if there really did exist a constriction where the minute bronchioles open into the air vesicles, just as a swelling of the bronchial tube may give rise to a sibilant rhonchus. This second theory is supported by the fact that the breath-sound over lung seems to differ in pitch and quality from the glottic murmur; while the first theory does not account satisfactorily for the disap¬ pearance of the greater part of the expiratory vesicular murmur. The cause of the vesicular murmur, therefore, is still doubtful, but it may be a combination of both theories, and it is admitted (Gee) that the nose, mouth, throat, unevenness of the windpipes, and the mouths of the air-sacs, may all be deemed possible causes of respira¬ tory murmurs. In practical auscultation it is sufficient to know that when the vesicular murmur is heard the subjacent lung-tissue is per¬ meable to air; and, when absent, the function of the air vesicles is interfered with. The object of auscultation of the lungs is threefold—viz., to learn (i) the type of the breathing; (2) the accompaniments; and (3) the character of the vocal resonance. The Breath-Sounds. —The normal breath-sounds are best learned practically, the vesicular murmur being heard more or less clearly over the whole surface of the lungs ; but at the level of the third dorsal vertebra behind, and the lower part of the manubrium sterni in front, it is replaced by broncho-vesicular (indeterminate) breathing, while at the apex of the right lung it is frequently harsh, and the expiratory portion prolonged. The vesicular type of breathing is described as faintly breezy and continuous, the inspiratory part being audible throughout, while the expiratory portion is weaker, and only heard at the beginning of expiration. It sometimes requires a deep inspiration to render the murmur clear, especially when the chest-walls are thick. In the aged and weakly the breath-sound is feeble and indistinct. In children it is harsh (puerile), because of the greater elasticity of the lung-tissue and the thinness of the chest-walls. The jerky or in¬ terrupted form of breathing occurs in the nervous, and disappears with deep inspiration ; but, abnormally, it may be due to the par¬ tially filled air-cells allowing of a secondary and later expansion. Prolonged expiration and harshness occur when there is diminished elasticity of the lung, or obstruction to the exit of air. Although harsh prolonged expiration occurs in general catarrhal conditions of the lung and bronchial tubes, it is chiefly of importance when localised. The same may be said of the interrupted and broncho-vesicular forms of the breath-sound ; and they are all of importance in relation to the diagnosis of incipient phthisis. Puerile breathing (in adults) is typically heard in the sound lung, when the other lung is collapsed by the pressure of a pleuritic effusion. The normal vesicular murmur—if there be no interference with its pro¬ duction by obstructions in the respiratory tract—may be rendered feeble or indistinct (distant) by enlarged organs and tumours, large