THE DISSECTION OF THE BACK 



the medulla spinalis made in different regions and at different 

 levels. 



In such sections the anlero-median fissure and the postero- 

 median septum and sulcus, which partially divide it along the 

 whole of its length into right and left halves, become obvious. 



The antero-median fissure is much shorter than the postero- 

 median septum. It dips dorsally to a commissure of white 

 matter, anterior white commissure, which connects the two 

 halves of the medulla spinalis ; and it contains a fold of pia 

 mater and branches of the anterior spinal vessels. The 

 postero-median sulcus is a shallow furrow which runs along 



Fasciculus gracilis 



Posterior funiculus 



Fasciculus cuneatus 



Formatio reticularis 

 Lateral funiculus 



Central canal 



Root of accessory 



nerve 



Anterior column of 

 grey matter 



Entering fila of 

 posterior nerve-root 



Posterior column of 

 grey matter 



Root of accessory 

 nerve 



Fila of anterior 

 nerve-root 



Anterior funiculus 



FIG. 79. Transverse section through the upper part of the 

 Cervical Region of the Medulla Spinalis. 



the posterior surface of the medulla spinalis in the median 

 plane, and the postero-median septum extends from the 

 bottom of the sulcus- to a transverse grey commissure called 

 the posterior commissure. 



The two halves of the medulla spinalis, thus marked off 

 from each other, are to all intents and purposes symmetrical, 

 and they are joined by a more or less broad band or com- 

 missure which intervenes between the anterior fissure and the 

 posterior septum. 



An inspection of the surface of each lateral half of the 



medulla spinalis brings into view a groove or furrow at some 



little distance from the postero-median sulcus ; it is called 



the postero-lateral sulcus. Along the bottom of this groove 



ii 13 a 



