VEINS OF THE BRAIN. 837 
veins are peculiar, inasmuch as they do not increase in size as they approach their 
terminations, and they are irregular in their relations to the arteries; as a rule the 
middle meningeal arteries alone possess two vene comites, the other meningeal 
arteries usually having only one accompanying vein. 
VEINS OF THE BRAIN. 
The veins of the brain include the veins of the cerebrum, of the mid-brain, of 
the cerebellum, of the pons, and of the medulla oblongata. They do not possess 
valves. 
Veins of the Cerebrum (vv. cerebri)—The cerebral veins are arranged in 
two groups, (@) the deep and (0) the superficial. 
The deep veins issue from the substance of the brain. The superficial veins lie 
upon its surface in the pia mater and the subarachnoid space. The terminal 
trunks of both sets pierce the arachnoid membrane and the inner layer of the dura 
mater, and open into the cranial venous sinuses. 
(a) The deep cerebral veins are the choroid veins, the veins of the corpora 
striata, the veins of Galen, and the inferior striate veins. 
Each choroid vein (v. chorioidea) is formed by the union of tributaries which 
issue from the choroid plexus in the descending horn of a lateral ventricle. It 
ascends along the lateral border of the velum interpositum, and passes forwards in 
the outer border of that fold of pia mater to the foramen of Monro, where it 
receives efferents from the choroid plexus of the third ventricle, and ends by unit- 
ing with the vein of the corpus striatum to form the vein of Galen. 
The vein of the corpus striatum, on each side, is formed by the union of tributaries 
which issue from the corpus striatum and from the optic thalamus. It runs for- 
wards between these bodies, in a groove in the floor of the lateral ventricle, and, 
after receiving tributaries from the walls of the anterior horn of the ventricle, 
including the septum lucidum, it terminates at the apex of the velum interpositum, 
where it joins the choroid vein to form the vein of Galen. 
The veins of Galen are three in number—a right and a left vein, and the vena 
magna Galen. 
Each lateral vein of Galen commences at the apex of the velum interpositum, 
near the foramen of Monro, by the union of the vein of the corpus striatum with 
the choroid vein. The two veins run backwards between the layers of the velum, 
and terminate beneath the splenium of the corpus callosum by uniting to form the 
vena magna Galeni. 
The tributaries which enter each vein, after its formation, are the basilar vein, the 
efferent veins from the choroid plexus of the third ventricle, and veins from the posterior 
part of the corpus callosum, the pineal body, the corpora quadrigemina, and the walls of 
the posterior cornu of the lateral ventricle. 
The vena magna Galeni (v. cerebri magna [Galeni]) passes backwards and 
shghtly upwards from its origin, and ends in the anterior extremity of the straight 
sinus. In addition to the two veins of Galen, by the union of which it is formed, 
it receives tributaries from the posterior parts of the callosal convolutions, from the 
inner and tentorial surfaces of the occipital lobes of the brain, and from the upper 
surface of the cerebellum. 
An inferior striate vein descends on each side from the substance of the corpus 
striatum, and, after passing through the anterior perforated space, ends in the 
basilar vein (p. 838), which, as already stated, is a tributary of the corresponding 
lateral vein of Galen. 
(6) The superficial cerebral veins are more numerous and of larger calibre 
than the cerebral arteries. They lie upon the surface of the cerebrum, they drain 
blood from the cerebral cortex, and they are divisible into two sets, the superior 
and the inferior. 
The superior cerebral veins (vy. cerebri superiores), twelve or more in number, 
lie in the pia mater and subarachnoid space on the upper and outer aspect of the 
cerebral hemispheres. They run inwards to the margin of the longitudinal fissure, 
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