SACEAL PART OF CORD. 



371 



series of those foramina, the right and left cords approach one another in their 

 progress downwards. The upper end of each is united to the last lumbar ganglion 

 by a single or a double intergauglionic cord ; and at the lower end they are 

 connected by means of a loop, in which a single median ganglion, ganglion impar or 

 coccygeal ganglion, placed on the fore part of the coccyx, is often found. The sacral 

 ganglia are usually four in number ; but the variation both in size and number is 

 more marked in these than in the thoracic or lumbar ganglia. 



Variety. In one instance the cord was found terminating at the second sacral nerve 

 (E. Fawcett, Journ. Anat., xxix, 329). 



Connection with spinal nerves. From the proximity of the sacral ganglia 

 to the spinal nerves at their emergence from the foramina, the communicating 



Fig. 235. SACRAL PORTION OF THE SYMPATHETIC CORDS 



OP AN INFANT, SLIGHTLY ENLARGED. (Rauber.) 



s 1 s 4, sacral ganglia ; c, coccygeal ganglion, 

 showing indications of its origin by the fusion of 

 two ganglia, and sending downwards branches which 

 run with the middle sacral artery ; ri, interfunicular 

 branches uniting the ganglia of the two sides ; below 

 these is seen a small interfunicular ganglion. 



branches are very short : there are often 

 two for one ganglion, and these are in 

 some cases connected with different sacral 

 nerves. The coccygeal nerve communi- 

 cates with the last sacral, or the coccygeal 

 ganglion. 



BRANCHES. The branches proceeding 

 from the sacral ganglia are much smaller 

 than those from other ganglia of the cord. 

 They are for the most part expended on the 

 front of the sacrum, and join the corre- 

 sponding branches from the opposite side. 

 Some filaments from one or two of the 

 upper ganglia enter the pelvic plexus, 

 while others go to form a plexus on the 

 middle sacral artery. From the loop con- 

 necting the two cords, filaments are given to the coccyx and to the ligaments about 

 it, and to the coccygeal gland. 



CONSTITUTION OF THE SACRAL SYMPATHETIC. 



There are no spinal fibres passing from the sacral nerves to the sympathetic cord, but the 

 latter contains medullated fibres which descend from the lumbar region and terminate in the 

 sacral ganglia. These fibres include vaso-constrictor and secretory fibres of the hind 

 limb, and the pilo-motor fibres of the hindmost part of the body and the tail in the cat 

 (Langley). 



The visceral branches of the sacral nerves (pclriv xplanchnics, Graskell) are equivalent 

 to white rami communicantes (p. 359), but they pass directly into the pelvic plexuses, where 

 a few of the fibres may turn upwards to the inferior mesenteric ganglion, 1 while the larger 

 number enter the plexuses of the pelvic viscera. They comprise : 



(Y/) Motor fibres to the longitudinal muscle, and inhibitory fibres to the circular 

 muscle of the rectum. 



1 Fibres ascending to the inferior mesenteric ganglion are described by Graskell in the dog, but they 

 were not found by Langley in the cat. 



