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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    A RECORD OF OUR PRESENT KNOWLEDGE OF ITS DEVELOPMENT, RELATIONSHIPS, STRUCTURE, AND MODE OF ACTION. BY J. F. HALLS DALLY, M.A., M.D. Cantab. I. INTRODUCTION. “Where an organ can be diverted from one, and set to discharge another function, there Nature will spare herself the expense of form- ing a new organ, and will adapt the old one to a new use. She is prodigal in the variety of her adaptations. She is niggard in the invention of new structures ” (Milne-Edwards). In variety of functional adaptation the diaphragm among the other muscles takes prominent place. Nor is it solely of importance because of its several functions, but chiefly by reason of its central position. Midway between thorax and, abdomen it touches and is touched by the chief atria mortis. Primarily a muscle concerned only with circulation, at a later developmental stage it has been put to many other uses, of which its action in respiration is the chief. In inspiration it enters into direct associate action with certain of the thoracic and spinal muscles; in expiration it is antagonised by the muscles of the abdomen; in deglutition it aids the buccal, pharyngeal, and oesophageal muscles; and in phonation, the laryngeal. These muscular actions are co-ordinated by means of neurons of association, whereby the nerves of the diaphragm are caused to enter into definite nerve-systems or combinations in order to effect the required movements. Primarily the abdominal musculature drove on the blood, the heart-force being expended chiefly in the gills; later, upon the introduc- tion of lungs in connection especially with ribs and negative pressure, the abdominal wall also became respiratory; in the beginning, however, both diaphragm and body-wall were cir- culatory. VOL. XLIV. L