THE SPINAL CORD 



8l 



epithelium and the lumen is often blocked with epithelial debris. The canal, 

 which is narrowest in the thoracic region, expands within the lower part of the 

 conus medullaris to form a fusiform dilatation, the ventriculus terminates. 



Posterior median sulcus and septum 

 Collaterals from fasciculus cuneat-us \ Posterior fun i en I us 



Dorsal root 

 I 



Dorsolateral fascicuhis (Lissauer} 

 ! Poster olateral sulcus 



Substantia gelati 



{4 "bex - 

 r 

 Lervix 



Posterior commissure 



Anterior gray - 

 commissure 



Anterior white com...- 

 Anterior column.*- 



Fig. 57. Section through the fifth lumbar segment of the spinal cord of a child. Pal-Weigert 



method. 



Dorsal roots of lumbar and sacral nerves 



Posterior fun iculus 



., 



: ''-'- Substantia gelatinosa 



Dorsolateral fasciculus 

 &5HB^. Posterior column 



^- Lateral funiculus 



'Anterior column 



*~ Ventral roots oj "lumbar and 

 sacral nerves 



Fig. 58. Section of the third sacral segment of the human spinal cord and the lumbosacral nerve 

 roots of the cauda equina. Pal-Weigert method. 



The White Substance. The long myelinated fibers of the cord, arranged in 

 parallel longitudinal bundles, constitute the white substance which forms a 



