520 SYMPATHETIC NERVE. 



reasons for believing it to be not only independent of the 

 brain and spinal marrow, but the original and formative 

 system to these latter portions as well as to the rest of 

 the animal body.* Well authenticated cases are recorded 

 of the absence of the brain, in acephalous foetuses ; and still 

 further, of the whole cerebro-spinal system. But no cases, 

 we believe,, are recorded of the sympathetic system being 

 "wanting, which seems fairly to show independence, as well 

 as priority of existence. 



The sympathetic, in the neck, presents three ganglia, 

 the superior cervical, middle, and inferior cervical, (Fig. 155.) 



The superior cervical ganglion is situated upon the rec- 

 tus capitis anticus, on the inside of the eighth and ninth 

 pair of nerves, and behind the internal carotid artery and 

 jugular vein. It is of an oval shape, and reddish color, ex* 

 tending from the first cervical vertebra, about half an inch 

 below the carotid foramen, to the third. 



Its branches are superior, inferior, internal, external^ 

 and anterior. The superior, two in number, ascend in the 

 carotid canal, where they form the carotid plexus. Here a 

 junction with the Vidian branch of the fifth and the sixth 

 occurs, and from this point filaments are traced into the 

 cavernous sinus, constituting the cavernous plexus, and 

 from thence to the Casserian ganglion also to the lentic- 

 ular ganglion, while others are found accompanying the 

 ophthalmic artery and its branches. 



The inferior branch forms the continued trunk of the 

 sympathetic, which connects this with the middle or lower 

 cervical ganglion. 



The internal branches proceed to the pharynx, larynx, 

 and heart. Those of the pharynx unite with the glosso- 

 pharyngeal and par vagum, forming the pharyngeal plexus. 

 The laryngeal unite with the branches of the superior la- 

 ryngeal nerve, while the cardiac descend the neck, behind 

 the sheath of the common carotid, entering the chest, along 



* See appendix to Sir Wilson Philip on " acute and chronic diseases," by 

 James H. Miller, M. D., former Professor of Anatomy in the Washington 

 Medical College of Baltimore. 



