1474 



A MANUAL OF ANATOMY 



placed. Posteriorly and laterally the tentorium cere belli is convex, 

 and is attached as follows, from behind forwards : (i) to the hori- 

 zontal ridge on the inner surface of the tabular part of the occipital 

 bone, where the process contains the lateral sinus ; (2) to the inner 

 aspect of the postero-inferior angle of the parietal bone, where the 

 process also contains the lateral sinus ; and (3) to the superior 

 border of the petrous part of the temporal bone, where the process 

 contains the superior petrosal sinus. Close to the apex of the 

 pars petrosa the outer and anterior borders of the tentorium cere- 

 belli cross, the outer border passing inwards to be attached to the 

 posterior clinoid process of the sphenoid bone, and the anterior 



Falx Cerebri 



Frontal.-— 

 Air-Sinus 



Styloid Process 



Tentorium Cerebelli 

 Mastoid Process 



Fig. 616. — The Falx Cerebri, Tentorium Cerebelli, and Venous Sinuses 

 OF THE Dura Mater (Left View). 



1. Superior Longitudinal Sinus 4. Lateral Sinus 



2. Inferior Longitudinal Sinus 5. Superior Petrosal Sinus 



3. Straight Sinus 6. Internal Jugular Vein 



border passing forwards to be attached to the anterior clinoid 

 process of that bone. 



The falx cerebelli extends forwards into the posterior cerebellar 

 notch, where it lies between the two cerebellar hemispheres. It is 

 falciform in outline. Superiorly it . is attached to the posterior 

 part of the inferior surface of the tentorium cerebelli in the median 

 line. Posteriorly it is attached to the internal occipital crest, and 

 this portion bifurcates interiorly, the two divisions being connected 

 to the lateral margins of the vermiform fossa. Along this posterior 



