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one, at the inner side of the cervix cornu, is called the posterior 

 vesicular column of Lockhart Clarke; a second, at the con- 

 cavity of the gray matter, the tractus intermediolateralis ; 

 and a third is found along the anterior part of the anterior 

 cornu. 



THE BRAIN (ENCEPHALON) 



The encephalon, or brain, is that part of the cerebrospinal 

 axis which, with its membranes, is contained in the cranium. 

 It is composed of the cerebrum, cerebellum, pons Varolii, and 

 medulla oblongata. 



The membranes of the brain are the dura, the pia, and the 

 arachnoid. 



The dura is similar in structure to the dura of the cord, but 

 differs from it in being closely attached to the cranial bones, 

 forming, in fact, their inner periosteum. It is continuous 

 with that of the cord at the foramen magnum, and with the 

 external periosteum of the cranial bones by means of its pro- 

 longations into the many foramina. It sends in various processes 

 to support and separate the different parts of the brain, and 

 its layers separate to form the cranial sinuses. In the vicinity 

 of the superior longitudinal sinus are to be found, on its outer 

 surface, several glandule Pacchionii. They may also be seen 

 on its inner surface and within the sinus, as well as on the 

 pia mater. 



The processes include the falces cerebri et cerebelli and the 

 tentorium cerebelli. 



The fair crrcbri separates the cerebral hemispheres. In 

 front it is narrow, becoming broader behind. Its upper convex 

 margin is attached to the vault of the cranium from the crista 

 galli in front to the internal occipital protuberance behind. 

 Its lower margin is free and concave anteriorly, while it is 

 attached posteriorly to the upper surface of the tentorium. 

 Above it lodges the superior, below the inferior longitudinal 

 sinus and part of the straight sinus. 



The fal.i; ccrcbcUi is triangular, and separates, inferiorly, 

 the lateral cerebellar lobes. It is attached above to the under 

 and posterior part of the tentorium, behind to the internal 

 occipital crest, below the torcular Herophili, and to the foramen 

 magnum, where it often divides into two parts, which ;iro 

 attached to its margins. 



