THE NERVOUS SYSTEM. 217 
thoracic region. In the sacral region there are no rami 
communicantes, and the ganglia are irregularly arranged. 
A median ganglion in the sacral region is known as the 
ganglion impar. There may be two median ganglia. The 
sympathetic cords terminate in the tail. 
Fic. 108. Cuter Part or Lert Harr or SyMPATHETIC SySTEM CAUDAD 
OF THE DIAPHRAGM. Semidiagrammatic. 
bl, Bladder; ce, cceliac axis; du, duodenum cut off; dia, diaphragm ; gr, 
anterior gastric plexus; g, ganglion; 1m, inferior mesenteric artery; 
il, external iliac artery; ng, dorsal branch of vagus (Fig. 103, ax); 
nl, ventral branch of vagus; oe, esophagus cut off ; p, superior mesen- 
teric plexus; plx, inferior mesenteric plexus; px, branches to dorsal 
gastric plexus; rm, renal plexus; sm, superior mesenteric artery; 
spn, splanchnic major or greater splanchnic nerve from the sym- 
pathetic cord; sg, semilunar ganglion; spc, sympathetic cord of left 
side. 
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