672 THE NERVOUS SYSTEM. 
from the lower part of the solar plexus on the capsular arteries. It is joined by 
branches from the diaphragmatic plexus above and from the renal plexus below. 
The nerves enter the substance of the suprarenal capsule. 
The renal plexus is derived from (1) branches of the semilunar ganglion, and 
(2) fibres from the aortic plexus, extending outwards along the renal artery to the 
hilus of the kidney. It receives also the least splanchnic nerve, and is connected 
by numerous branches to the suprarenal plexus. 
d. The superior mesenteric plexus is inseparable above from the cceliac plexus, 
and is joined on either side by fibres from the semilunar ganglion. It is continuous 
below with the aortic plexus. A separate detached ganglionic mass (superior 
mesenteric ganglion) is present in the plexus. Accompanying the superior mesen- 
teric artery, the plexus forms subordinate plexuses around the branches of the 
vessel. The plexuses in the mesentery at first surround the intestinal arteries, 
but near the intestine they form fine plexuses between the layers of the mesentery, 
from which branches pass to the wall of the gut. This plexus supplies the small 
intestine, ceecum, vermiform appendix, ascending and transverse portions of the 
colon. 
e. The aortic plexus is the continuation downwards of the solar plexus around 
the abdominal aorta. It is continuous above with the superior mesenteric and 
solar plexuses; it is reinforced by the peripheral branches of the lumbar ganglated 
cord of the sympathetic; and it is connected with the hypogastric plexus below 
by the hypogastric nerves. Besides investing and supplying the aorta, the plexus 
contributes to various subordinate plexuses on the branches of the artery. It 
contributes to the suprarenal and renal plexuses, and it gives rise to the spermatic 
or ovarian and the inferior mesenteric plexuses. 
The spermatic plexus invests and accompanies the spermatic artery. It is 
derived from the aortic plexus, and receives a contribution from the renal plexus. 
It supphes the spermatic cord and testicle. 
The ovarian plexus in the female arises like the spermatic plexus. It accom- 
panies the ovarian artery to the pelvis, and supples the ovary, broad ligament, and 
Fallopian tube. It forms communications in the broad lHgament with the uterine 
plexus (from the pelvic plexus), and sends fibres to the uterus. 
The inferior mesenteric plexus is a derivative from the aortic plexus, prolonged 
along the inferior mesenteric artery. It forms subordinate plexuses on the 
branches of the artery (colic, sigmoid, and superior hemorrhoidal), and is dis- 
tributed to the descending colon, iliac colon, pelvic colon, and upper part of the 
rectum. 
The hypogastric nerves form the continuation of the aortic plexus into the 
pelvic cavity. They consist of numerous plexiform bundles of nerve fibres which 
descend along the front and back of the bifurcation of the aorta and the origin of 
the common iliac arteries, over the sacral promontory, where, becoming inextricably 
mingled, they constitute the hypogastric plexus. 
The hypogastric plexus is continued downwards and forwards in front of the 
sacrum on either side of the rectum, and ends in the pelvic plexuses. 
The pelvic plexuses are formed as stated by the separation of the hypo- 
gastric plexus into two halves on either side of the rectum. Each is joined by 
fibres from the upper part of the sacral portion of the ganglated cord of the 
sympathetic, and by the visceral branches (white rami communicantes) from the 
sacral nerves. Accompanying the internal iliac artery and its branches, each 
pelvic plexus gives off subordinate plexuses for the pelvic viscera. 
a. The hemorrhoidal plexus supplies the rectum, and joins the superior hemor- 
rhoidal plexus from the inferior mesenteric plexus. 
b. The vesical plexus accompanies the vesical arteries to the bladder-wall. 
Besides supplying the wall and mucous membrane of the bladder, it forms sub- 
ordinate plexuses for the lower part of the ureter, the vesicula seminalis, and the 
vas deferens. 
c. The prostatic plexus is of considerable size. It is placed on either side of 
the gland, and besides supplying its substance and the prostatic urethra, sends 
offsets to the neck of the bladder and the vesicula seminalis. It is continued 
il 
