THE PELVIC PLEXUS. 809 



plexus, which accompanies the gastro-epiploica sinistra artery along the convex 

 border of the stomach. 



The superior mesenteric plexus is a continuation of the lower part of the great 

 solar plexus, receiving a branch from the junction of the right pneumogastric 

 nerve with the coeliac plexus. It surrounds the superior mesenteric artery, which it 

 accompanies into the mesentery, and divides into a number of secondary plexuses, 

 which are distributed to all the parts supplied by the artery viz. pancreatic branches 

 to the pancreas ; intestinal branches, which supply the whole of the small intestine ; 

 and ileo-colic, right colic, and middle colic branches, which supply the correspond- 

 ing parts of the great intestine. The nerves composing this plexus are white in 

 color and firm in texture, and have numerous ganglia developed upon them near 

 their origin. 



The aortic plexus is formed by branches derived, on each side, from the solar 

 plexus and the semilunar ganglia, receiving filaments from some of the lumbar 

 ganglia. It is situated upon the sides and front of the aorta, between the origins 

 of the superior and inferior mesenteric arteries. From this plexus arise part of 

 the spermatic, the inferior mesenteric, and the hypogastric plexuses ; and it dis- 

 tributes filaments to the inferior vena cava. 



The inferior mesenteric plexus is derived chiefly from the left side of the aortic 

 plexus. It surrounds the inferior mesenteric artery, and divides into a number of 

 secondary plexuses, which are distributed to all the parts supplied by the artery 

 viz. the left colic and sigmoid plexuses, which supply the descending and sigmoid 

 flexure of the colon ; and the superior haemorrhoidal plexus, which supplies the 

 upper part of the rectum and joins in the pelvis with branches from the pelvic 

 plexus. 



The Hypogastric Plexus. 



The Hypogastric Plexus supplies the viscera of the pelvic cavity. It is situated 

 in front of the promontory of the sacrum, between the two common iliac arteries, 

 and is formed by the union of numerous filaments, which descend on each side 

 from the aortic plexus and from the lumbar ganglia. This plexus contains no 

 evident ganglia; it bifurcates, below, into two lateral portions, which form the 

 pelvic plexuses. 



The Pelvic Plexus. 



The pelvic plexus (sometimes called inferior hypogastric] supplies the viscera 

 of the pelvic cavitv, is situated at the side of the rectum in the male, and at the 

 side of the rectum and vagina in the female. It is formed by a continuation of the 

 hypogastric plexus, by branches from the second, third, and fourth sacral nerves, 

 and by a few filaments from the first two sacral ganglia. At the point of junction 

 of these nerves small ganglia are found. From this plexus numerous branches are 

 distributed to all the viscera of the pelvis. They accompany the branches of the 

 internal iliac artery. 



The inferior hsemorrhoidal plexus arises from the back part of the pelvic 

 plexus. It supplies the rectum, joining with branches of the superior hgemor- 

 rhoidal plexus. 



The vesical plexus arises from the fore part of the pelvic plexus. The nerves 

 composing it are numerous, and contain a large proportion of spinal nerve-fibres. 

 They accompany the vesical arteries, and are distributed at the side and base of 

 the bladder. Numerous filaments also pass to the vesiculae seminales and vas 

 deferens ; those accompanying the vas' deferens join, on the spermatic cord, with 

 branches from the spermatic plexus. 



The prostatic plexus is continued from the lower part of the pelvic plexus. 

 The nerves composing it are of large size. They are distributed to the pros- 

 tate gland, vesiculse seminales, and erectile structure of the penis. The nerves 



