560 



CINERITIOUS NEURINE OF THE SPINAL CORD. 



Fig. 220.f 



Fig. 219.* The transverse sections 



& c of the cord show that it is 



solid throughout, though it 

 has erroneously been as- 

 serted by some -anatomists 

 to possess a canal in its centre. Its outer portion is composed 

 exclusively of the white or^brous neurine, and its interior con- 

 tains a considerable portion of the cineritious or pulpy neurine, 

 called sometimes the nucleus of the spinal marrow. 

 The quantity of cineritious or gray matter included, varies 

 very much at different heights of the cord, as seen in the follow- 

 ing cuts. 



Every where in the spi- 

 nal cord the medullary en- 

 velops the cineritious neu- 

 rine, the reverse of what 

 takes place in the lobes of 

 the cerebrum and cerebel- 



* Fig. 2 19 represents transverse sections of the spinal cord at different heights, 

 the large proportion of the central cineritious neurine compared with the me- 

 dullary, and the variation in shape and size of the former, at different portions 

 of the spine ; the size of the medulla being always greater at the points, where 

 the largest number of roots to the spinal nerves are given off. The anterior 

 surface of the cord, which is seen above, shows the anterior median fissure ; 

 opposite to it below, is seen the posterior. 



The shape of each symmetrical portion of the cineritious nucleus, is more or 

 less semilunar ; the anterior extremity or horn being blunt or round, and pre- 

 senting towards the point where the anterior roots of the nerves are given off. 

 The posterior extremity is acuminated, and terminates in the lateral fissure from 

 which arise the posterior roots of the nerves, and which divides each half of the 

 spinal marrow, into the posterior, and antero-lateral column, a, Is a section 

 opposite the eleventh dorsal vertebra, b, a section opposite the fifth dorsal, and 

 c, one opposite the fourth cervical. 



f Fig. 220, d, is a representation of a]transverse section of the spinal marrow, 

 opposite the third cervical vertebra. The bulk of the cineritious neurine in this, 

 contrasted with that of a section immediately below it, opposite the fourth cer- 

 vical, (see fig. 219,) from which the brachial plexus in part arises, is very small. 

 e, Is a transverse section of the medulla oblongata, a little above the middle of 

 the corpora olivaria showing the arrangement of its cineritious neurine, in three 

 portions, corresponding with the divisions of the medulla oblongata, into three 

 bodies. 1. Cineritious nucleus belonging to the corpus pyramidale. 2. Cine- 

 ritious nucleus belonging to the corpus olivare of the same side. The dark line 

 below fig. 2, belongs to the corpus pyramidale. Both of the figures in this cut 

 are taken from Solly. 



