378 SPECIAL ANATOMY. 



municantes, art. fossce Sylvii, choroidea and profunda 

 cerebri. 



b. The cerebellum by : artt. cerebelli inferior, media and su- 

 perior. 



Veins do not accompany the arteries ; they are found plentifully 

 on the surface, and fall into the sinus of the dura mater. 



a. In the interior of the cerebrum pass : 



1 . V. choroidea, arising at the anterior point of cornu descend, of 

 the lateral ventricle ; it ascends in the plexus choroid., the 

 veins of which, as well as those of the cornu Ammonis, it 

 receives and unites with. 



'2. V. corporis striati, which passes from the stria cornea be- 

 tween corp. striatum and lhalam. n. optici, whilst still in the 

 lateral ventricle, to 



3. V. cerebri interna s. magna. This enters into the third 

 ventricle through foram. Monroi, passes into its plexus cho- 

 roid. from before backwards, unites between corp. cattos. and 

 quadrigem. with that of the other side into a short (two to 

 three lines thick) trunk, the vena Galeni, which, at the junc- 

 tion oftentorium andfalx cerebri, enters into the last and the 

 sinus quartus. 



b. The veins of the cerebellum open into the Vv. vertebrates, into 

 the sinus transvers., petrosi and occipitalis posterior. 



627. The Spinal Marrow, Medulla spinalis, (AusXos, |cri<n]. 



This is the medullary column, flattened from before backwards, 

 which passes downwards into the canalis spinalis as the immediate 

 continuation of the medulla oblongata, surrounded, like the brain, 

 by membranes. Its surface is white. Its length measures, in the 

 adult from fifteen to eighteen inches ; its circumference, at the 

 inferior extremity of the cervical portion = eighteen lines, in the 

 lumbar portion = twelve (intumescentia cervicalis and lumbalis), 

 whilst the dorsal portion is the smallest, on which account the 

 nerves arising from it are also the smallest. Its superior extremity 

 passes uninterruptedly into the medulla oblongata at the foramen 

 magnum ; its inferior termination, on account of the long lumbar 

 and sacral nerves, which lying close together, are called cauda 

 equina, reaches, in the foetus, as far as the sacrum, in the adult to 

 the second lumbar vertebra, where it terminates in a conical form 

 (conus meduttaris) and presents two ganglia, as an exception, only. 

 On its anterior and posterior surfaces a fissure is observable in the 

 middle line (Jissura mediana) ; at the base of the anterior fissure a 



