NERVES OF THE PELVIS. 



519 



The remaining branches of the plexus, viz., the small and great sciatic 

 nerves, and muscular offsets to the gluteus, gemelli, and quadratus femoris, 

 are described with the lower limb. (Dissection of the Buttock.) 



Dissection. The gangliated cord of the sympathetic that lies in front 

 of the sacrum may be examined now : its several ganglia (three or four), 

 and their branches, will come into view on the removal of the areolar 

 tissue. 



Fig. 177. 



a. Urinary bladder. 

 6. Rectum. 



c. Levator aui. 



d. Coccygeus. 

 Nerves : 



4? and 5 I, the last two lumbar nerves, 

 which form by their union the 

 lumbo-sacral cord. 



1 S tooS, the five sacral nerves, form- 

 ing the sacral plexus. 



1 c. Coccygeal nerve. 



1. Upper gluteal nerve. 



2. Branch of levator anl. 



3. Branch to the bladder. 



4. Branch of sphincter ani. 



5. Branch of coccygeus. 



6. Common branch of 4 S, o S, and 1 

 c, for the back of the coccyx. 



DISSECTION OF THE SACRAL NERVES AND PLEXUS (altered from Heule). 



SYMPATHETIC NERVE. In the pelvis the sympathetic nerve consists of 

 a gangliated cord, and of a plexus on each side. 



The GANGLIATED CORD (fig. 177) lies on the front of the sacrum and 

 internal to the series of apertures in that bone. Interiorly it converges to 

 its fellow, and is united with it by a loop in front of the coccyx, on which 

 is situate a single median ganglion (gang, impar). Each cord is marked 

 by ganglia at intervals, the number varying from three to five : from them 

 branches of communication pass outwards to the spinal nerves, and some 

 filaments are directed inwards in front of the sacrum. 



The connecting branches are two to each ganglion, gray and white, and 

 are very short : the gray cord unites the ganglion with the spinal nerve, 

 but the white one is continued over the ganglion to the visceral plexus 

 (Beck). 



The internal branches are small, and communicate around the middle 

 sacral artery with the brandies of the opposite side. From the first, or 

 first two ganglia, some filaments are furnished to the hypogastric plexus ; 

 and from the terminal connecting branches, and from the ganglion in front 

 of the coccyx, offsets descend over that bone. 



The PELVIC PLEXUSES (lateral inferior hypogastric) are two in number, 

 right and left, and are continuous with the lateral prolongations of the 



