974 



NEUROLOGY 





which proceeds to the hypogastric or pelvic plexuses from which postganglionic 

 fibers are distributed to the pelvic viscera. Motor fibers pass to the smooth muscle 

 of the descending colon, rectum, anus and bladder. Vasodilators are distributed 

 to these organs and to the external genitalia, while inhibitory fibers probably pass 

 to the smooth muscles of the external genitalia. Afferent sympathetic fibers conduct 

 impulses from the pelvic viscera to the second, third and fourth sacral nerves. 

 Their cells of origin lie in the spinal ganglia. 



Submaxillary ganglion 



? 



"-Sublingual gland 

 Submaxillary gland 



I.Th. 



FIG. 842. Sympathetic connections of the submaxillary and superior cervical ganglia. 



THE THORACOLUMBAR SYMPATHETICS. 



The thoracolumbar sympathetic fibers arise from the dorso-lateral region of the 

 anterior column of the gray matter of the spinal cord and pass with the anterior 

 roots of all the thoracic and the upper two or three lumbar spinal nerves. These 

 preganglionic fibers enter the white rami communicantes and proceed to the 

 sympathetic trunk where many of them end in its ganglia, others pass to the pre- 

 vertebral plexuses and terminate in its collateral ganglia. The postganglionic 

 fibers have a wide distribution. The vasoconstrictor fibers to the bloodvessels of the 

 skin of the trunk and limbs, for example, leave the spinal cord as preganglionic 

 fibers in all the thoracic and the upper two or three lumbar spinal nerves and 

 terminate in the ganglia of the sympathetic trunk, either in the ganglion directly 

 connected with its ramus or in neighboring ganglia. Postganglionic fibers arise 



