1044 



TlfE NERVOUS SYSTEM 



The paired subordinate plexuses of the coeliac. — (1) The phrenic (diaphragmatic) plexuses 



consist of fibres from the upper part of the coeUac ganglia, which follow the inferior phrenic 

 arteries and their branches on the under surface of the diaphragm (fig. 790). Filaments are 

 given off by the roots of the plexuses to the suprarenal bodies, and others unite with the ter- 

 minal branches of the phrenic nerves. The point of junction with the right phrenic nerve is 

 marked by the phrenic ganglion, from which branches are distributed to the inferior vena cava-, 

 to the right suprarenal body, and to the hepatic plexus. 



(2) The suprarenal plexuses are comparatively large plexuses, formed mainly by branches 

 from the coeliac' (semilunar) ganglia. However, fibres come to them from the coeliac plexus 



Fig. 790. — Abdominal Plexuses of the Sympathetic. (After Toldt, "Atlas of Human 

 Anatomy," Rebman, London and New York.) 

 Coeliac plexus Left vagus nerve 



Phrenic plexus 



Right vagus nerve 



Superior gastric plexus 

 Phrenic plexus 



Suprarenal plexus 



_1I —Splenic plexus 



Hepatic plexus 



Ductus 



choledochus 



Superior 

 mesenteric" 

 plexus 



Aortic plexus 





•Coeliac ganglion 



")>^Renal plexus 



Superior 

 mesenteric 

 ganglion 



Spermatic plexus 



Lumbar ganglia 



(\lnferior mesen- 

 teric plexus 



along the suprarenal arteries, from the phrenic plexus along the inferior phrenic arteries, and 

 from the renal plexus along the inferior suprarenal arteries. They are distributed to the 

 sub.stance of the suprarenal bodies. Cell-bodies of sympathetic neurones are enclosed within 

 the suprarenal bodie.s forming intrinsic ganglia. The medulla of the suprarenal is of ecto- 

 dermal origin and considered as derived from undeveloped components of the sympathetic 

 nervous system. 



(.'ij The renal plexuses receive fibres from the lower part of the co'liac ganglia and from 

 the cd'liac and aortic i)lcxuses. They also receive filaments from the least splanchnic nerves, 

 when these nerves arc preH(!nt, and sometimes filaments from the small splanchnic nerves and 

 from the first lumbar ganglion of the sympathetic trunk. These plexuses pass along the renal 

 arteries into the substance of the kidneys. Most of the fibres of each renal plexus are grey fibres, 

 and as they pass to the kidneys small renal ganglia are present upon them. Both renal 

 plexuses give oranches to the corresponding spermatic plexuses and to the ureter, and the 

 right renal plexus gives filaments also to the inferior vena cava. 



