THE SYMPATHETIC PLEXUSES 377 



upper five or six supply the aorta, the vertebrte and their 

 ligaments, and enter into the posterior pulmonary plexus. 



The lower six or seven unite to form the splanchnic nerves. 



The large splanchnic arises from the fifth or sixth to the 

 ninth or tenth, descends obliquely along the spine, and pierces 

 the crus of the diaphragm to end in the semilunar ganglion, 

 sending branches to the renal plexus and suprarenal capsule. 



The lesser splanchnic arises from the tenth and eleventh, 

 and, piercing the crus, ends in the celiac plexus, communicating 

 with the preceding and the renal plexus. 



The least splanchnic arises from the last ganglion, and pierces 

 the crus, joining the renal plexus and sending branches to the 

 celiac plexus. 



THE SYMPATHETIC NERVES OF THE LUMBAR REGION 



In the lumbar portion the ganglia lie in front of the spine, 

 along the inner side of the psoas. They communicate with 

 the ganglia above and below, and by two branches with each 

 of the spinal nerves. 



Branches. Some cross the aorta to join the aortic plexus; 

 some cross the common iliacs and enter the hypogastric plexus; 

 others supply the vertebrae and their ligaments. 



THE SYMPATHETIC NERVES OF THE SACRAL REGION 



In the sacral portion the ganglia lie internal to the anterior 

 sacral foramina, sending branches to the ganglia above and 

 below, and two branches each to the sacral nerves. The re- 

 maining branches join together and send filaments, some to 

 enter the pelvic plexus and others to form a plexus on the 

 middle sacral artery. The two lowest ganglia on each side 

 are joined by a loop over the coccyx, on which is the ganglion 

 impar. 



THE SYMPATHETIC PLEXUSES 



The cardiac plexus lies at the base of the heart, and consists 

 of a superficial and a deep part. 



