494 



THE SPIXAL CORD. 



been described on each side of the cord, corresponding with the lines of 

 attachment of the anterior and posterior roots of the spinal nerves. 



The posfcrior lateral fismre (fig. 3-47, 4) is a superficial depression 

 along the line of attachment of the posterior roots. 



The anterior lateral fissure, which is often described in the line of 

 the origin of the anterior roots of the nerves, has no real existence as a 

 groove. The fibres of these roots in fact, unlike the ]30sterior, do not 

 dip into the spinal cord in one narrow line, but spread over a space of 

 some breadth. Thus, each lateral half of the cord is divided superficially 

 by the posterior lateral fissure into a posterior and an antero-lateral 

 column. The attachment of the anterior roots, however, divides the 

 latter into anterior and lateral portions. 



On the posterior surface of the cord, and most evidently in the upper 



Fig. 347. Fig. 3i7. — Different 



Views of a Portion of 

 THE Spinal Cord from 

 THE Cervical Region 

 •WITH THE Roots of 

 THE Nerves. Sligttly 

 enlarged (Allen Thom- 

 son). 



In A, tlie anterior sur- 

 face of the si3ecimen is 

 showTi, the anterior nerve- 

 root of tlie right side 

 being divided ; in B, a 

 view of the right side is 

 given ; in C, the iipper 

 surface is shown ; in D, 

 the nerve-roots and gan- 

 glion are shown from 

 below. 1, the anterior 

 median fissure : 2, pos- 

 terior median fissure ; 3, 

 anterior lateral depres- 

 sion, over which the ante- 

 rior nerve-roots are seen 

 to spread ; 4, posterior 

 lateral groove into which 

 the posterior roots are 

 seen to sink ; 5, anterior 

 roots passing the ganglion ; 

 5', in A, the anterior root divided ; 6, the posterior roots, the fibres of which pass 

 into the ganglion, 6' ; 7, the united or compound nerve ; 7', the posterior primary 

 branch, seen in A and D to be derived in part from the anterior and in part from the 

 posterior root. 



part, there are two slightly marked longitudinal furrows situated one 

 on each side, close to the posterior median fissure, and marking off, at 

 least in the cervical region, a slender tract, named the posterior median 

 column. Between the anterior and posterior roots of the spinal_ nerves, 

 on each side, the cord is convex, and sometimes presents a longitudinal 

 mark corresponding with the line of attachment of the ligamentum 

 denticulatum. 



INTERNAL STRUCTUKE OF THE SPINAL CORD. 



The spinal cord consists of white and grey nervous substance. The 

 white matter, forming by far the larger portion of the cord, is 



