io8 



BIOLOGICAL PHYSICS 



Dxu 



function to the Batrachian "lymph hearts," and from its 

 being traversed by 'muscular fibres and supplied with 

 ganglionic nerve cells, therefore possessed of the power of 

 emptying itself, or, in other words, it possesses the power of 



acting as a " bladder " for the caudal 

 extremity of the cerebro-spinal 

 cavity. 



The pathological and clinical 

 aspects of these views will, we 

 think, be seen to have most impor- 

 tant bearings on both the scientific 

 and practical application of medical 

 and surgical principles and practice. 

 In still further pursuing our 

 enquiries into the role of the 

 cerebro-spinal circulation, we would 



Lr M/^llllllilMlilK l l ux>J ' L Allude in more detail to the more 

 purely nervine aspect of the subject, 

 and its associations on the basis of 

 continuity with the cerebro-spinal 

 part or aspect of the subject. 



Anatomically the brain, spinal 

 cord, and nervous system proper 

 are suspended, so to speak, within 

 a fluid medium or covering con- 

 tinuous from the cerebro-spinal 

 cavity to the ultimate termination 



FIG. 39. POSTERIOR VIEW OF THE LOWER END 



OF THE SPINAL CORD WITH THE CAUDA EQUINA 



AND SHEATH. (Allen Thomson.) ^. 



The sheath has been opened from behind and stretched 

 towards the sides ; on the left side all the roots of the 

 nerves are entire ; on the right side both roots of the 

 first and second lumbar nerves are entire, while the rest 

 have been divided close to the place of their passage 

 through the sheath. The bones of the coccyx are 

 sketched in their natural relative position to show the 

 place of the filum terminale and the lowest nerves. 



, placed on the posterior median fissure at the middle 

 of the lumbar enlargement of the cord ; b, b, the ter- 

 minal filament, drawn slightly aside by a hook at its 

 middle, and descending within the dura-matral sheath ; 

 6', b' ', its prolongation beyond the sheath and upon the 

 back of the coccygeal bones ; c, the dura-matral sheath; 



d, double foramina in this for the separate passage of 

 the anterior and posterior roots of each of the nerves; 



e, ligamentum denticulatum ; Dx, and Dxu, the tenth 

 and twelfth dorsal nerves; Li, and Lv, the first and 

 fifth lumbar nerves ; Si, and Sv, the first and fifth sacral 

 nerves ; Ci, the coccygeal nerve. 



