874 



NEUROLOGY 





tentorium cerebelli. Its upper margin is convex, and attached to the inner surface 

 of the skull in the middle line, as far back as the internal occipital protuberance; 

 it contains the superior sagittal sinus. Its lower margin is free and concave, and 

 contains the inferior sagittal sinus. 



The tentorium cerebelli (Fig. 766) is an arched lamina, elevated in the middle, 

 and inclining downward toward the circumference. It covers the superior surface 

 of the cerebellum, and supports the occipital lobes of the brain. Its anterior border 

 is free and concave, and bounds a large oval opening, the incisura tentorii, for the 

 transmission of the cerebral peduncles. It is attached, behind, by its convex border, 

 to the transverse ridges upon the inner surface of the occipital bone, and there 

 encloses the transverse sinuses; in front, to the superior angle of the petrous part 



Optic nerve 



Diaphragma sellce \ 

 Free margin (if tentorium \ 



Internal carotid artery 

 Oculomotor nerve 

 I Attached margin of tentorium ' 



End of superior sagittal sinus 

 FIG. 766. Tentorium cerebelli seen from above. 



of the temporal bone on either side, enclosing the superior petrosal sinuses. At 

 the apex of the petrous part of the temporal bone the free and attached borders 

 meet, and, crossing one another, are continued forward to be fixed to the anterior 

 and posterior clinoid processes respectively. To the middle line of its upper surface 

 the posterior border of the falx cerebri is attached, the straight sinus being placed 

 at their line of junction. 



The falx cerebelli is a small triangular process of dura mater, received into the 

 posterior cerebellar notch. Its base is attached, above, to the under and back part 

 of the tentorium; its posterior margin, to the lower division of the vertical crest 

 on the inner surface of the occipital bone. As it descends, it sometimes divides 

 into two smaller folds, which are lost on the sides of the foramen magnum. 



The diaphragma sellae is a small circular horizontal fold, which roofs in the sella 

 turcica and almost completely covers the hypophysis; a small central opening 

 transmits the infundibulum. 



