The intracranial circulation : an essay to which was awarded the first prize of the Boylston Medical Society in 1867 / by Thomas Dwight.
- Thomas Dwight
- Date:
- 1867
Licence: Public Domain Mark
Credit: The intracranial circulation : an essay to which was awarded the first prize of the Boylston Medical Society in 1867 / by Thomas Dwight. 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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![Indeed, unless the existence of such a communica- tion be admitted, it is impossible to explain how the equilibrium of the fluids of the brain can be main- tained when the amount of the blood is suddenly altered. This fluid varies in amount from two to eight ounces, and is in inverse ratio to that of the blood, and in direct ratio to the age of the subject. It is in the most intimate relation with the blood- vessels, which, in certain places, — the choroid plex- uses for example, — are bathed in it; an arrange- ment eminently calculated to promote osmosis. When from anv cause the Other contents of the t/ cranium are increased this fluid is diminished. In atrophy of the brain, or when it is very amemic, the reverse takes place. The way in which it va- ries with the amount of blood, is well shown in cases of spina bifida; the tumor swells during ex- piration and sinks during inspiration. Ecker s description of the movements of the cere- bro-spinal fluid is so clear and satisfactoiy, that 1 cannot forbear giving it. “At the moment of ex- piration, the vertebral sinuses, which are numerous and ramifying exterior to the theca, are distended with blood. This distension must cause an approxi- mation of the theca towards the spinal cord, and this inward or centripetal movement will create a pres- sure upon the fluid within the theca. This contained fluid seeks an outlet which it finds more readily to- wards the inside of the cranium than elsewhere. The cerebral veins are, indeed, distended at the same period, ])ut the unyielding sinuses within the cranium](https://iiif.wellcomecollection.org/image/b22344895_0016.jp2/full/800%2C/0/default.jpg)
