THE DURA MATER OF THE BRAIN. 3 



of the sella Turcica is a continuation of the ophthalmic vein, 

 the large cavernous sinus (s. cavernosus] (Fig. 3), which receives 

 at the sphenoidal fissure the spheno-parietal sinus (s. ala parva], 

 the course of which is along the posterior border of the lesser 

 wing of the sphenoid bone. At the posterior clinoid process the 



Fig. i. Sagittal section of skull, showing falx cerebri, falx cerebelli, part of 

 tentorium cerebelli and sinuses. (After Morris's Anatomy.') 



a. Falx cerebri. b. Superior sagittal sinus, c. Inferior sagittal sinus, d. Great cere- 

 bral vein. e. Straight sinus, f. Tentorium cerebelli. g. Transverse sinus, h. Superior 

 petrosal sinus, i. Falx cerebelli. j. Seventh and eighth nerves, k. Ninth, tenth, and 

 eleventh nerves. 1. Twelfth nerve, m. Second cervical nerve, n. Fourth nerve, o. Third 

 nerve, p. Second nerve, q. Middle meningeal artery, r. Internal carotid artery, s. Ver- 

 tebral artery, t. Fifth nerve, u. Sixth nerve, v. Inferior petrosal sinus, w. First cervical 

 nerve, x. Ligamentum denticulatum. 



cavernous sinus divides into the superior petrosal sinus (s. petro- 

 sus superior] and the inferior petrosal sinus (s. petrosus inferior}. 

 The sinus intercavernosus anterior and sinus intercavernosus 

 posterior extend across the hypophyseal fossa, and join the two 

 cavernous sinuses together, and these four communicating sinuses 



