On the mechanism of respiration / by Francis Sibson, Esq.

  • Francis Sibson
Date:
1846
Catalogue details

Licence: Public Domain Mark

Credit: On the mechanism of respiration / by Francis Sibson, Esq. Source: Wellcome Collection.

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    wards, as the proportion of the thoracic to the abdominal viscera increases, a forward movement of the lower cartilages takes place ; this gradually increases until, in adult life, the forward movement of the conjoint cartilages and of the lower portion of the sternum is even greater than that of the superior cartilages and the upper portion of the sternum. 100. Old age*. In the aged, the costal cartilages being ossified, each rib and cartilage forms as it were one inflexible bone; the costal cartilages still hinge on the sternum. The costal respiration is performed by the elevation and consequent variation in the position of the curves of the ribs. There is no yielding of the cartilages, consequently the lower part of the sternum and the conjoint costal cartilages are pushed forward to a greater extent than they are in the youthful. The thoracic respiration, though considerable, is not so great as in the adult or young man ; to make amends, diaphragmatic respi- ration is increased, and the angle formed between the opposite costal cartilages below the sternum is more open. The old man does not require the energetic breathing of the young. The bulk of the lung increases, the air-cells being enlarged, in the aged, and the chest gradually takes on more and more the form that it has on an ordinary or even a deep inspiration ; consequently the movement of the ribs on inspiration is not so great in the old man as it is in the middle-aged. The increase of the dorsal arch due to the permanent inspiratory form, causes the stooping, and, in part, the short- ening of the aged. 101. Varieties in respiratory movements induced by disease. Permit me to hint at the influences of some diseases of the lungs on the respira- tory movements of the chest. If the larynx be narrowed so as to permit but little air to enter the lungs, the diaphragm descends so rapidly that the air has not time to fill up those portions of the lungs displaced downwards by the diaphragm ; the consequence is that the pres- sure of the atmosphere forces backwards and inwards the costal walls on the lungs. If the summit of the lung be affected with phthisis, the corresponding portion of the chest is but little dilated, and the ribs are depressed and almost motionless over the diseased portion of lung; sometimes the rib even falls in at the beginning of inspiration. In inflammation of the lower lobe of the lung, that lobe is distended by diseased secretions ; the chest over it is permanently expanded and has little or no respiratory movement; at the same time the upper portion of the same side of the chest is less actively inspiratory. If the diaphragm be inflamed on one side, that side does not act; the diaphrag- matic ribs and the hypogastric region do not move forwards on the affected, though they do on the healthy side.
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