A treatise on headachs, their various causes, prevention, and cure / [George Hume Weatherhead].

  • George Weatherhead
Date:
1841
Catalogue details

Licence: Public Domain Mark

Credit: A treatise on headachs, their various causes, prevention, and cure / [George Hume Weatherhead]. Source: Wellcome Collection.

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    which exertion is usually performed; — secondly, a similar effect is produced by the angles which both the carotid and vertebral arteries make before they reach the interior of the head ;—and thirdly, this end is further attained by the in¬ ordinate disproportion between the area of the branches of these two arteries and that of their trunks. The great consideration which nature evinces in diminishing the impetus of the blood on the brain is beautifully illustrated in ruminating ani¬ mals, where, from the dependent position of the head in browsing, the circulation within it would be otherwise so apt to become disordered: — I allude to the subdivision of the carotid artery within the pars petrosa into a multitude of branches, and their reunion afterwards, before emerging from the carotid canal and entering the brain, to be again subdivided. This curious arrangement of the vessels, to which there is nothing similar in all comparative anatomy (except in the iliac arteries of the sloth), was observed as early as the time of Galen, and by him first called the rete mirabile. Another peculiarity in the circulation carried on in the head, is the mode in which the blood is returned from it. Most of the veins of the brain terminate in sinuses ; and the mouths of many of
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