640 NERVOUS SYSTEM. 



The lumbar ganglia, four in number, are situated in the lumbar region, 

 upon the bodies of the vertebrae. They are connected with the ganglia above 

 and below and with each other by the sympathetic cord, receiving, like the 

 other ganglia, filaments from the spinal nerves. Their branches of distribu- 

 tion form the aortic lumbar plexus and the hypogastric plexus and follow the 

 course of the blood-vessels. 



The four or five sacral ganglia and the ganglion impar are situated by 

 the inner side of the sacral foramina and in front of the coccyx. These are 

 connected with the ganglia above and with each other, and they receive fila- 

 ments from the sacral nerves, there being generally two branches of commu- 

 nication for each ganglion. The filaments of distribution go to all of the 

 pelvic viscera and blood-vessels. The inferior hypogastric, or pelvic plex- 

 us is a continuation of the hypogastric plexus above, and receives a few fila- 

 ments from the sacral ganglia. The uterine nerves go to the uterus and the 

 Fallopian tubes. In the substance of the uterus the nerves are connected 

 with small collections of ganglionic cells. The sympathetic filaments are 

 prolonged into the upper and lower extremities, following the course of the 

 blood-vessels and terminating in their muscular coat. 



The filaments of the sympathetic, at or near their terminations, are con- 

 nected with ganglionic cells, not only in the heart and the uterus, but in the 

 blood-vessels, lymphatics, the coccygeal gland, the submucous and the mus- 

 cular layer of the entire alimentary canal, the salivary glands, pancreas, 

 excretory ducts of the liver and pancreas, the larynx, trachea, pulmonary 

 tissue, bladder, ureters, the entire generative apparatus, suprarenal capsules, 

 thymus, lachrymal canals, ciliary muscle and the iris. In these situations 

 nerve-cells have been demonstrated by various observers, and it is probable 

 that they exist everywhere in connection with the terminal filaments of this 

 system of nerves. 



General Properties of the Sympathetic Ganglia and Nerves. The sym- 

 pathetic ganglia and nerves possess a dull sensibility, which is particularly 

 marked in the ganglia. That the nerves contain afferent fibres, is shown by 

 certain reflex phenomena. 



Stimulation of the sympathetic produces muscular movements, but these 

 are confined generally to non-striated muscular fibres, to which these nerves 

 are largely distributed. The muscular movements do not immediately follow 

 stimulation of the nerves, but there is a long, latent period. The muscular 

 contraction, also, persists for a time and the subsequent relaxation is slow. 

 The induced current applied to the splanchnic nerves does not produce 

 movements of the intestines, but these movements are excited by the con- 

 stant current (Legros and Onimus). The properties of the vaso-motor 

 nerves will be considered separately. 



The sympathetic ganglia are connected with the motor and sensory 

 divisions of the cerebro-spinal system. Some of the ganglia and nerve- 

 plexuses are directly dependent for their action upon the cerebro-spinal 

 system, while others are capable, at least for a time, of independent action. 

 Among the latter, are the ganglia of the heart, the intestinal plexuses, the 





