The diaphragm in man : a record of our present knowledge of its development, relationships, structure, and mode of action / by J.F. Halls Dally.

  • Dally, John Frederick Halls, 1877-1944.
Date:
[1908?]
Catalogue details

Licence: In copyright

Credit: The diaphragm in man : a record of our present knowledge of its development, relationships, structure, and mode of action / by J.F. Halls Dally. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    the thoracic muscles, and relaxes whilst their action is still going on. In a series of experiments Bert (®^) found that after (i) longitudinal section of the cord from the first to the fourth pair of cervical nerves, (2) complete transection of the cord above the first pair, and (3) complete transection below the second pair, each half of the diaphragm still contracts. Section below the third pair abolishes diaphragmatic move- ments. Rokitansky pointed out that, when the medulla is put out of action, young rabbits to whom strychnine has been given can still perform respiratory movements, Langendorff and Nitschmann discovered spinal centres apart from the medulla capable of reflex or automatic action. Christiani located an inspiratory centre in the third ventricle and an expiratory centre in the corpora quadrigemina. Later still Mosso lias shown that respiratory movements of face, thorax, diaphragm, and abdomen are mutually independent, that alternation exists between the respiratory movements of thorax and abdomen, by means of which, when the force of the diaphragmatic contraction lessens, the thoracic action increases, and vice versd, that periods of intermission in the movements of the diaphragm occur while the thoracic move- ments continue uniformly equal, and that hiccough can produce at intervals strong contraction of the diaphragm without thoracic participation. More recently still, as mentioned above, Pansini has described in lower mammals the exist- ence of diaphragmatic ganglia, and has called attention to the rhythmical contraction of this muscle which takes place iii hysteria apart from thoracic movements. IX. TYPES OF RESPIRATION. Although custom has sanctioned the division of respiration into two “types”—thoracic and abdominal—yet this classifica- tion is by no means exact. “Thoracic respiration” really means maximum increase in all diameters of the upper part of the thorax, and “ abdominal respiration ” a similar effect in the lower part of the thorax. In the former case the breathing is mainly upper costal, and in the latter case lower costal. Pure thoracic or pure abdominal respiration seldom occurs ; breathing, though usually “ mixed,” being labelled according to the then dominant factor. Nor is it easy to draw a hard and fast line between the two groups on account of the varia- tions and transitions in type which frequently befall. Under the stress of altered conditions, especially in young people with elastic thorax, each is capable of rapid transformation.