The anatomy and philosophy of expression as connected with the fine arts / by Sir Charles Bell.

  • Charles Bell
Date:
1872
Catalogue details

Licence: Public Domain Mark

Credit: The anatomy and philosophy of expression as connected with the fine arts / by Sir Charles Bell. Source: Wellcome Collection.

Provider: This material has been provided by King’s College London. The original may be consulted at King’s College London.

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    of the chest in breathiu, duriiifj which tlic venous blood is thus interruj^ted. As we draw in the breath, the blood flows along the veins with perfect facilit}', because the superior opening of the chest is then enlarged, and the suction, which draws air into the windpipe, has also the effect of increasing the force of the current of returning blood. But when we expel the air, and thereby diminish the area of the chest, an obstruction takes ])lace in the flow of blood in the veins, and if the act of expiration be strong, regurgitation may be produced. This interruption, and retrograde motion of the blood in the large veins of the neck, gorges the smaller vessels; the effect of which may be seen in a person seized with a fit of coughing or of sneezing: for his face then becomes suffused with red, and the superficial veins turgid with blood. It is therefore obvious that if the veins of the surface of the head become congested, in such violent conditions of breathing, the deeper veins, returning the blood from the Brain and the Eye, will also be over-distended from the same cause. Consequently, the delicate textures of these important organs will be in danger of suffering serious injury from the loaded and turgid condition of the veins. But both organs are defended from such dangers by a beautiful arrangement of tlie muscles of the neck, which cover and protect the venous trunks. These muscles act in sympathy with the movements of respiration ; so as to compress the large veins when the chest is contracted, and there is a tendency to regurgitation of the blood; and to take pressure off them, when the chest is expanded, and the channel to the heart is free. It is further to be noticed, that the flat web of muscular fibres which covers the eye—the orbicularis muscle, by which we wink, and shut the eyes—is a part of the same provision. It acts in compressing the eyeball whenever the chest is violently contracted, as in coughing, &c.; by that means it closes the veins at the back of the orbit, and prevents engorgement of the fine branches which ramify on the delicate coats within tlie eyeball;* * The orbicularis muscle is wanting in animals which have not the same con- centrated apparatus for breathing as man. I have shewn elsewhere that in man and mammalia another provision exists besides that mentioned in the text, for guarding the eye against the irregularities of tlie venous circulation. The small