94 



Membranes of the Brain and Spinal Cord. 



434. The Brain and its Membranes, 



View from above. 



The Falx cerebri descends vertically in the longitudinal fissure 

 between the two hemispheres of the brain; it is narrow in front, where 

 it is attached to the Crista yalli, broader behind, where it is connected 

 with the tentorium. Along its upper convex border, which is attached 

 to the inner surface of the skull as far back as the internal occipital 

 protuberance, runs the superior 1 o n g i t u d i n a 1 s i n u s, Sinus falci- 

 formis superior; its free concave margin is turned towards the Corpus 

 callosiun, but does not touch it. The Falx cerebelli descends from the back 

 part of the tentorium, with which it is connected, along the internal 

 occipital crest, towards the Foramen maynuin, bifurcating there into two 

 smaller folds ; its sinus is not constant. The Tentorium cerebelli is placed 

 between the posterior lobes of the cerebrum and the hemispheres of the 

 cerebellum; its anterior free border presents a large oval opening for the 

 transmission of the Crura cerebri. The pituitary fossa of the body of the 

 sphenoid bone is partially closed by a fourth process, the Opercullum sellae 

 turcicae. 



