Volume 1

The physiology of man : designed to represent the existing state of physiological science as applied to the functions of the human body / by Austin Flint.

  • Flint, Austin, 1836-1915.
Date:
1866-1874
Catalogue details

Licence: Public Domain Mark

Credit: The physiology of man : designed to represent the existing state of physiological science as applied to the functions of the human body / by Austin Flint. Source: Wellcome Collection.

    384/516 (page 378)
    after a careful consideration of the relative position of the parts. Levatores Costarum.—The action of these muscles cannot be mistaken. They have immovable points of origin, the transverse processes of twelve vertebrae from the last cervical to the eleventh dorsal, and, spreading ont like a fan, are at- tached to the upper edges of the ribs between the tubercles and the angles. In inspiration they contract and assist in tlie elevation of the ribs. They are more developed in man than in the inferior animals. Auxiliary Muscles of Inspiration.—The muscles which have just been considered are competent to increase the ca- pacity of the thorax sufficiently in ordinary respiration ; there are certain muscles, however, which are attached to the che&* and the upper part of the spinal column, or upper extremities, which may act in inspiration, though ordinarily the che&t is the fixed point, and they move the head,, neck, or arms. These muscles are brought into action when the movements of respiration are exaggerated. When this exaggeration is but slight and physiological, as after exercise, certain of them (ordinary auxiliaries) act for a time, until the tranquillity of the movements is restored. But when there is obstruction in the respiratory passages, or when respiration is excessively difficult from any cause, threatening suffocation, all the muscles which can by any possibility raise the chest are brought into action. The principal ones are put down in the table under the head of extraordinary auxiliaries. Most of these muscles can voluntarily be brought into play to raise the chest, and the mechanism of their action can in this way be demonstrated. Serratus Posticus Superior.—This muscle arises from the ligamentum nuchse, the spinous processes of the last cervical and upper two or three dorsal vertebrae, its fibres passiifg