THE LUMBAR PORTION OF THE GANGLIATED CORD. 873 



pleura costalis ; the last two are, however, anterior to the rest, being placed on the 

 side of the bodies of the eleventh and twelfth dorsal vertebrae. The ganglia are 

 small in size and of a grayish color. The first, larger than the rest, is of an 

 elongated form and frequently- blended with the last cervical. They are connected 

 together by cord-like prolongations from their substance. 



The t>.rter/ial branches from each ganglion, usually two in number, communi- 

 cate with each of the dorsal spinal nerves. 



The internal branches from the six upper ganglia are very small ; they supply 

 filaments to the thoracic aorta and its branches, besides small branches to the 

 bodies of the vertebrae and their ligaments. Branches from the third and fourth, 

 and sometimes also from the first and second ganglia, form part of the posterior 

 pulmonary plexus. 



The internal branches from the six lower ganglia are large and white in color; 

 they distribute filaments to the aorta and unite to form the three splanchnic nerves. 

 These are named the great, the lesser, and the smallest or renal splanchnic. 



The great splanchnic nerve is of a white color, firm in texture, and bears a 

 marked contrast to the ganglionic nerves. It is formed by branches from the 

 thoracic ganglia between the sixth and tenth, receiving filaments (according to Dr. 

 Beck) from all the thoracic ganglia above the sixth. These roots unite to form a 

 large round cord of considerable size. It descends obliquely inward in front of 

 the bodies of the vertebrae along the posterior mediastinum, perforates the crus of 

 the Diaphragm, and terminates in the semilunar ganglion, distributing filaments 

 to the renal and suprarenal plexus. 



The lesser splanchnic nerve is formed by filaments from the tenth and eleventh 

 ganglia and from the cord between them. It pierces the Diaphragm with the 

 preceding nerve and joins the coeliac plexus. It communicates in the chest with 

 the great splanchnic nerve, and occasionally sends filaments to the renal plexus. 



The smallest, or renal, splanchnic nerve arises from the last ganglion, and, 

 piercing the Diaphragm, terminates in the renal plexus and lower part of the 

 coeliac plexus. It occasionally communicates with the preceding nerve. 



A striking analogy appears to exist between the splanchnic and the cardiac 

 nerves. The cardiac nerves are three in number; they arise from the three 

 cervical ganglia, and are distributed to a large and important organ in the thoracic 

 cavity. The splanchnic nerves, also thi-ee in number, are connected probably with 

 all the dorsal ganglia, and are distributed to important organs in the abdominal 

 cavity. 



The Lumbar Portion of the Gangliated Cord. 



The lumbar portion of the gangliated cord is situated in front of the vertebral 

 column along the inner margin of the Psoas muscle. It consists usually of four 

 ganglia, connected together by interganglionic cords. The ganglia are of small 

 size, of a grayish color, shaped like a barleycorn, and placed much nearer the 

 median line than the thoracic ganglia. 



The xn/',->'i>r and inferior branches of the lumbar ganglia serve as communi- 

 cating branches between the chain of ganglia in this region. They are usually 

 single and of a white color. 



The external branches communicate with the lumbar spinal nerves. From the 

 situation of the lumbar ganglia these branches are longer than in the other regions. 

 They are usually two in number from each ganglion, but their connection with the 

 spinal nerves is not so uniform as in other regions. They accompany the lumbar 

 arteries around the sides of the bodies of the vertebrae, passing beneath the fibrous 

 arches from which some of the fibres of the Psoas muscle arise. 



Of the internal branches, some pass inward, in front of the aorta, and help to 

 form the aortic plexus. Other branches descend in front of the common iliac 

 arteries, and join over the pi'omontory of the sacrum, helping to form the hypo- 

 gastric plexus. Numerous delicate filaments are also distributed to the bodies of 

 the vertebras and the ligaments connecting them. 



