THE SYMPATHETIC NERVE SYSTEM. 613 



terlacing in an intricate manner they form the cardiac plexuses. With the 

 exception of fibers arising in and coming from the inferior cervical ganglion 

 there is no reason for believing that the branches of the cardiac plexus are 

 distributed to the heart-muscle. The fibers having this distribution are 

 derived for the most part from the inferior cervical and in small part from 

 the first thoracic ganglion. (See page 305.) The thoracic, lumbar, and 

 sacral ganglia also give off visceral branches which pass for the most part 

 to neighboring structures, though from the lower lumbar and sacral ganglia 

 branches pass to viscera in the lower abdominal and pelvic regions. 



In accordance with the law of distribution and relations of the fibers of the 

 sympathetic ganglia to peripheral organs, it can be assumed that to whatever 

 organ the visceral branches are distributed they ultimately terminate in the 

 non-striated muscle-cells of the walls of the blood-vessels and the walls of 

 hollow viscera, and in some situations the epithelium of glands as well. 



The Pre-vertebral Ganglia. The pre-vertebral ganglia are located in 

 the abdominal cavity. The semilunar, the renal, and the superior mesenteric 

 are situated in the neighborhood of the cceliac axis and on a level with the 

 adrenal bodies. From the ganglia an enormous number of visceral branches 

 are given off which interlace in a very intricate manner forming what is 

 known as the solar plexus. Subdivisions of this plexus taking their names 

 from the regions to which they are distributed are known as the gastric, 

 renal, adrenal, splenic, hepatic, and superior mesenteric. The terminals of 

 the fibers composing these plexuses are distributed to the blood-vessels of 

 the stomach, kidney, adrenal body, liver, and small intestine; to the muscle- 

 walls of the stomach and small intestine as well as the sphincter muscles sur- 

 round the gastro-duodenal, the pyloric and the ileo-colic orifices. 



From the inferior mesenteric ganglion situated close to the origin of the 

 inferior mesenteric artery visceral fibers are given off, which also interlace 

 to form the hypogastric plexus, from which fibers pass to the muscle-walls 

 of the colon, bladder, uterus, vagina and to the blood-vessels of the pelvic 

 viscera. 



The Peripheral Ganglia. The peripheral ganglia as previously stated 

 are in more or less close relation with tissues and organs in different regions 

 of the body. Among the members of this group may be mentioned the 

 ciliary or opthalmic, the spheno-palatine, the otic and the submaxillary 

 ganglia; the ganglia in the walls of the heart, the respiratory organs, of the 

 stomach, intestines and base of the bladder (the pelvic). The situation 

 of the first four of the ganglia, (the cephalic,) and the distribution of their 

 visceral branches have been considered in connection with the oculo-motor, 

 facial, and glosso-pharyngeal nerves. The ganglia of the heart and intestines 

 have been considered in connection with the physiologic action of these 

 organs. 



THE ANATOMIC RELATION OF THE CENTRAL NERVE SYSTEM TO 

 THE SYMPATHETIC GANGLIA. 



The central nerve system is associated with the sympathetic ganglia 

 through the intermediation of fine medullated nerve-fibers which have 

 their origin in nerve-cells located in three different regions, viz.: i. in 



