THE MEDULLA SPINALIS OR SPINAL CORD 



751 



, and is adherent to, the dura mater; it extends downward from the apex of the 

 tubular sheath and is attached to the back of the first segment of the coccyx. 

 The filum terminale consists mainly of 

 fibrous tissue, continuous above with 

 that of the pia mater. Adhering to its 

 outer surface, however, are a few strands 

 of nerve fibers which probably represent 

 rudimentary second and third coccygeal 

 nerves; further, the central canal of the 

 medulla spinalis extends downward into 

 it for 5 or 6 cm. 



Enlargements. The medulla spinalis 



Decussation of 

 the pyramids 



is not quite cylindrical, being slightly 

 lattened from before backward; it also 



Anterior median 

 fissure 



Conus inedullaris 

 Posterior nerveroots 



Filum lerminale 



Postero- 



intermediate 



sulcus 



___ Cervical 

 enlargement 



Posterior 

 median sulcus 



Postero- 

 ' lateral sulcus 



Lumbar 

 enlargement 



-Conus 



Filum 



FIQ. 662. Cauda equina and filum terminale seen 

 from behind. The dura mater has been opened and 

 spread out, and the arachnoid has been removed. 



Ventral aspect Dorsal aspect 

 Fj. 663. Diagrams of the medulla spinalis. 



