CEREBRAL. 463 



the superior longitudinal sinus, in the opposite direction to the course of the 

 blood. 



The Inferior Anterior Cerebral Veins commence on the under surface of the 

 anterior lobes of the brain, and terminate in the cavernous sinuses. 



The Inferior Lateral Cerebral Veins commence on the lateral parts of the 

 hemispheres and at the base of the brain : they unite to form from three to five 

 veins, which open into the lateral sinus from before backwards. 



The Inferior Median Cerebral Veins, which are very large, commence at the 

 fore part of the under surface of the cerebrum, and from the convolutions of the 

 posterior lobe, and terminate in the straight sinus behind the vena3 Galeni. 



The Deep Cerebral or Ventricular Veins (venae Galeni) are two in number, 

 one from the right ventricle, the other from the left. They are each formed 

 by two veins, the vena corporis striati and the choroid vein. They pass back- 

 wards, parallel with one another, inclosed within the velum interpositum, and 

 pass out of the brain at the great transverse fissure, between the under surface 

 of the corpus callosum and the tubercula quadrigemina, and enter the straight 

 sinus. 



The vena corporis striati commences in the groove between the corpus striatum 

 and thalamus options, receives numerous veins from both of these parts, and 

 unites behind the anterior pillar of the fornix with the choroid vein, to form one 

 of the vense Galeni. 



The choroid vein runs along the whole length of the outer border of the 

 choroid plexus, receiving veins from the hippocampus major, the fornix and 

 corpus callosum, and unites; at the anterior extremity of the choroid plexus, 

 with the vein of the corpus striatum. 



The Cerebellar Veins occupy the surface of the cerebellum, and are disposed in 

 three sets, superior, inferior, and lateral. The superior pass forwards and inwards, 

 across the superior vermiform process, and terminate in the straight sinus ; some 

 open into the venae Galeni. The inferior cerebellar veins, of large size, run 

 transversely outwards, and terminate by two or three trunks in the lateral sinuses. 

 The lateral anterior cerebellar veins terminate in the superior petrosal sinuses. 



SINUSES OF THE DURA MATER. 



The sinuses of the dura mater are venous channels, analogous to the veins, 

 their outer coat being formed by the dura mater ; their inner, by a continuation 

 of the serous membrane of the veins. They are twelve in number, and are 

 divided into two sets: 1. Those situated at the upper and back part of the skull. 

 2. The sinuses at the base of the skull. 



1. The sinuses of the upper and back part are the 



Superior longitudinal. Straight sinus. 



Inferior longitudinal. Lateral sinuses. 



Occipital sinuses. 



The Superior Longitudinal Sinus occupies the attached margin of the falx 

 cerebri. Commencing at the crista Galli, it runs from before backwards, groov 

 ing the inner surface of the frontal, the adjacent margins of the two parietal 

 and the superior division of the crucial ridge of the occipital bone, and terminates 

 by dividing into the two lateral sinuses. This -sinus is triangular in form, 

 narrow in front, and gradually increasing in size as it passes backwards. On 

 examining its inner surface, it presents the internal openings of the cerebral 

 veins : these vessels are, for the most part, directed from behind forwards, and 

 chiefly open at the back part of the sinus, their orifices being concealed by fibrous 

 areolas; numerous fibrous bands, chordse Willisii, are also seen, which extend 

 transversely across its inferior angle ; and lastly, some small, white, projecting 

 bodies, the glandulae Pacchioni. This sinus receives the superior cerebral veins. 



