The human brain : histological and coarse methods of research : a manual for students and asylum medical officers / by W. Bevan Lewis.
- Lewis, William Bevan, 1847-1929.
- Date:
- 1882
Licence: Public Domain Mark
Credit: The human brain : histological and coarse methods of research : a manual for students and asylum medical officers / by W. Bevan Lewis. 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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![4. Local bulgings may be dae to aneiirismal dilatations, to the different forms of arteritis—atheroma, tubercle, sy]3hilitic gmnmata, or to the impaction of a thrombus or embolus. The arteries at the base will be found often exceedingly atheromatous, tortuous, knotty, and white ; the amount of atheromatous material occluding even the larger cerebral arteries, often converting the smaller branches into irregular knotty cords. The student should never infer from the aspect or feel of such a vessel that it is occluded, but he should always make a section across the mass of diseased tissue, when, if the vessel be permeable, the orifice is readily detected. Note particularly the branches which are occluded. If the bulging be due to inflammatory swelling and exudation into the outer tunics of the artery, it will be observed that corresponding to the site of lesion the vessel is dilated—a condition due to paralysis of the muscular coat of the vessel, together with implication of the elastic outer tunic. Make a section across the inflamed tissue, and observe how readily the elastic or outer coat may be stripped from the muscular by means of a forceps; also how friable and easily separable are the muscular fibres of the media. The inner coat will be probably deeply stained by haematiii, or may be eroded and covered by an adherent clot immediately beneath the inflamed patch. When a clot appears to obstruct the calibre of a blood-vessel, the character of the clot should be taken into consideration, its fibrinous constitution, stage of organization, adhesion to vascidar walls, its form, prolongations, and appearance of its section. The sheath and outer tunic of the arteries should be closely examined, especially in the neigh- bom'hood of the Sylvian fissure and island of Eeil, for tuber- cular or syphilitic growths. Especial care must be taken to exactly note the arterial tunics involved, so as to discrimi- nate between ordinary endarteritis, resulting in atheromatous degeneration, and the syphilitic node or gumma involving the outer coats, and the tubercular nodules involving the arterial sheaths, all of which lesions may give rise to blocking, con- c 2](https://iiif.wellcomecollection.org/image/b21292966_0037.jp2/full/800%2C/0/default.jpg)
