CHAP, i.] 



THE SPINAL CORD. 



r. IT. dr. 



883 



D2 



Ls. 



D8. 



Sac. 



FIG. 104. DIAGRAM ILLUSTRATING SOME OF THE FEATURES OF THE SPINAL CORI> 



AT DIFFERENT LEVELS. (ShemngtOD.) 



All the figures are drawn to scale, and represent the cord magnified four 

 times. They shew the differences at different levels in the shape and size of the 

 cord, in the outline of the grey matter, and in the relative position of the anterior 

 and posterior fissures, and also shew the variations at different levels of the several 

 * tracts ' of the white matter. 



C 2 at the level of the second cervical nerve, C 5 of the fifth cervical, C s of the eighth 

 cervical. D 2 of the second thoracic, D 5 of the fifth thoracic, L x of the first 

 lumbar, L 5 of the fifth lumbar, and Sac. of the second sacral nerve. 



The shading of the tracts is the same as in Fig. 100; but in the median posterior 

 column of D 2 the areas of fibres coming from the sacral nerves s. r., and lumbar 

 nerves I. r. are distinguished from the area, d. r. of fibres belonging to the 

 thoracic nerves. In C 8, no distinction is made between any of these sets 

 of fibres; in L5 only fibres of sacral nerves are represented; in Lj D 8 D 5 , the 

 more dorsal small portion corresponds to sacral fibres and the next to lumbar, 

 or lumbar thoracic nerves. 



in Fig. 104. In these, combined with the three figures just referred 

 to, it will be observed that the serial increase and decrease of the 



