636 THE SYMPATHETIC NERVES AND GANGLIA. 



]-)oiat, terminates in the semilunar ganglion, frequently sending some 

 filaments to the renal plexus and the suprarenal body. 



The splanchnic nerve is remarkable from its white colour and 

 firmness, which are owing to the preponderance of the spinal nerve- 

 fibres in its composition. 



Varieties. — In the chest the great splanchnic nerve is not unfrequently divided 

 into parts, and forms a plexus with the small splanchnic nerve. Occasionally 

 also a small ganglion (ganglion splanchnicum) is formed on it over the last dorsal 

 vertebra, or the last but one ; and when it presents a plexiform arrangement, 

 several small ganglia have been observed on its divisions. 



In eight instances out of a large number of bodies, Wrisberg observed a fourth 

 splanchnic nerve (nervus splanchnicus supremus). It is described as formed by 

 offsets from the cardiac nerves, and from the lower cervical as well as some of 

 the upper thoracic ganglia. ('' Observ. Anatom. de Nerv. Viscerum particula 

 prima," p. 25, sect. 3.) 



Small Splanchnic Nerve. — The small or second splanchnic nerve 

 springs from the tenth and eleventh ganglia, or from the neighbouring 

 part of the cord. It passes along with the preceding nerve, or separately 

 through the diaphragm, and ends in the coeliac plexus. In the chest 

 this nerve often communicates with the large splanchnic nerve ; and in 

 some instances it furnishes filaments to tlie renal plexus, especially if 

 the lowest splanchnic nerve is very small or wanting. 



Smallest Splanchnic Nerve. — This nerve (nerv. renalis posterior — 

 Walter) arises from the twelfth thoracic ganglion, and communicates 

 sometimes with the nerve last described. After piercing the diaphragm, 

 it ends in the renal plexus, and in the inferior part of the coeliac plexus. 



LUMBAR PART OF THE GANGLIATED CORD. 



In the lumbar region the two gangliated cords approach one another 

 more nearly than in the thorax. They are placed before the bodies of 

 the vertebrffi, each lying along the inner margin of the psoas muscle ; 

 and that of the right side is partly covered by the vena cava. 



The ganglia are small, and of an oval shape. They are commonly 

 four in number, but occasionally, when their number is diminished, 

 they are of larger size. 



Connection with spinal nerves. — In consequence of the greater distance 

 at which the lumbar ganglia, are placed from the intervertebral foramina 

 the branches of connection with the spinal nerves are longer than in 

 other parts of the gangliated cord. There are generally two connecting 

 branches for each ganglion, but the number is not so uniform as it is 

 in the chest ; nor are those belonging to any one ganglion connected 

 always with the same spinal nerve. The connecting branches accom- 

 pany the lumbar arteries, and, as they cross the bodies of the vertebrte, 

 are covered by the fibrous bands which give origin to the larger psoas 

 muscle. 



Branches. — The branches of these ganglia are uncertain in their 

 number. Some join a plexus on the aorta ; others descending go to 

 form the hypogastric plexus. Several filaments are distributed to the 

 vertebrce and the ligaments connecting them, 



SACRAL PART OF THE GANGLIATED CORD. 



Over the sacrum the gangliated cord of the sympathetic nerve is 

 much diminished in size, and gives but few branches to the viscera. 



