Inflammation Of The Sinuses Of The Dura Mater arises from injuries of the cranium, in consequence of a concussion of the dura mater near the sinus, or of a direct injury of the latter from fragments of bones, etc. It is frequently observed to arise from inflammation of the dura mater in the neighborhood of a sinus, and from inflammation and suppuration of the bone. A tolerably frequent example of the latter mode of derivation presents itself in the inflammation of the sigmoid sinus,1 arising from caries of the petrous portion of the temporal bone, whence it commonly spreads, with considerable rapidity, to the internal jugular vein. In some rare cases, this form of phlebitis is owing to coagulation of the blood (metastasis); and as it is almost invariably accompanied, under these conditions, by a purulent exudation, we not unfrequently find that the walls of the sinus exhibit incipient suppuration. We have repeatedly seen cases in which the inflammation, after attacking the cavernous sinus, had extended by means of the superior ophthalmic to the anterior facial vein, and exhibited a diffused redness over the skin of the face.

In inflammation of the longitudinal sinus, the venous trunks opening into it are occluded at the convexity of the hemispheres.

2. The last-named vessels occasionally become the seat of coagulation, in consequence of disease of the blood, which is either spontaneous, or induced by the absorption of pus. This coagulation, in its turn, gives rise to phlebitis, which, together with the inflammation of the sinus, is frequently associated with meningitis.

1 [The anterior portion of the lateral sinus].