ANATOMY IN A NUTSHELL. 



333 



The pia mater is the inner membrane of the cord. It is closely adherent 

 to the cord and sends septa into the anterior and posterior fissures of the cord. 

 The linea splendens is the thickened line of pia mater along the anterior median 

 line. The ligamenta denticulata are fibrous bands which are attached to the 

 median lateral aspect of the pia mater from the level of the foramen magnum to 

 the level of the first lumbar vertebra. The ligaments are midway between the 

 anterior and posterior nerve roots. There are about twenty-one ligaments on 

 each side, extending from the pia mater to the dura mater, carrying the arach- 

 noid along which it, not piercing it. The highest one of the processes is placed 

 between the hypoglossal nerve and the vertebral artery. 



PLATE CLIII. 



LEFT 



LATERAL LIGAMENT 



SITE OF THE SPIGELIAN LOBE 



INFERIOR VENA CAVA 



The Superior Surface of the Liver. 



The reticula is a network of gray matter, enclosing white fibers in its meshes. 

 It is situated at the base of the posterior horn externally, directly opposite the 

 columns of Clarke. The columns of Clarke are two symmetrically placed tracts 

 of medium sized nerve cells of thespinal cord, latero-dorsal of the central canal, 

 confined chiefly to the dorsal region, but also extending a little above and below it. 



LESSON XCV. ' 



The anterior and posterior nerve roots of the spinal cord emerge from the 

 antero-lateral and postore -lateral aspects of the cord respectively, and form a 

 double row on each side of it. The anterior roots arise from the anterior horn 

 of the gray matter and contain motor fibers; the posterior roots arise from the 

 posterior horn and contain sensory fibers. 



The central canal is in the centre of the gray commissure, and is lined with 



