THE SOLAR AND PELVIC PLEXUSES. 671 
becomes continued into the hypogastric plexus, 
which again forms the chief origin of the pelvic 
plexuses. 
The semilunar ganglia constitute the 
chief ganglionic centres in the solar plexus. 
They are irregular in form. They are often 
partially subdivided, and one detached portion 
at the lower end is named the aortico-renal 
ganglion. Other small scattered masses of cells 
are present in the coeliac plexus (ganglia 
celiaca). At the upper end the semilunar 
ganglion receives the great splanchnic nerve. 
The aortico-renal ganghon at its lower end 
receives the smaller splanchnic nerve. Branches 
from the ganglion radiate in all directions— 
inwards to join the ccehac plexus, upwards to 
form the diaphragmatic plexus, outwards to the 
suprarenal plexus, downwards to the renal, 
superior mesenteric, and aortic plexuses. 
The cceliac plexus forms a considerable 
plexiform mass surrounding the eceliac axis. It 
consists of a dense meshwork of fibres with 
gangha (g. eceliaca) intermingled, joined by 
numerous branches from the semilunar gang- 
hon on each side, and by branches from the 
right phneumogastric nerve. It is continuous 
below with the superior mesenteric and aortic 
plexuses. Investing the cceliac axis, it forms 
subsidiary plexuses which accompany the 
branches of the artery. The coronary plexus 
supplies branches to the esophagus and stomach; 
the hepatic plexus supplies branches to the 
liver and gall-bladder, stomach, duodenum, and 
pancreas ; and the splenic plexus sends offsets to 
the spleen, pancreas, and stomach. 
Subordinate plexuses are formed on the 
aorta and its branches by nerves derived from 
the solar plexus (semilunar ganglia and cceliac 
plexus). 
a. The diaphragmatic plexus consists of 
fibres arising from the semilunar ganglion, and 
accompanies the inferior phrenic. artery. Be- 
sides supplying the diaphragm, it gives branches 
to the suprarenal plexus, and on the right side 
to the inferior vena cava, on the left side to 
the cesophagus. It communicates on each side 
with the phrenic nerve. At the junction of the 
plexus and phrenic nerve of the right side a Bye laleee 
ganglion is formed (diaphragmatic ganglion ). Fic. 481.— THE Menace oe THE 
6b. The suprarenal plexus is of considerable SYMPATHETIC SYSTEM IN THE THORAX, 
size. It is mainly derived from branches of ABDOMEN, AND PELVIS. 
the semilunar ganglion, reinforced by nerves 7-1-125 L.1-5; S.1-5; Co, Anterior primary 
divisions of spinal nerves, connected to the 
gangliated cord of the sympathetic by 
rami communicantes, white (double lines) and gray (single lines); OEs, Gisophagus and cesophageal 
plexus ; Ao, Aorta and aortic plexus ; Va, Vagus nerve joining cesophageal plexus ; 8.1, Great splanchnic 
nerve ; X, Great splanchnic ganglion; $8.2, Small splanchnic nerve; 8.3, Least splanchnic nerve ; Co, 
Coronary artery and plexus ; Spt, Splenic artery and plexus ; H, Hepatic artery and plexus ; S.L, Semi- 
lunar ganglion ; Di, Diaphragm ; S.R, Supra-renal capsule; Re, Renal artery and plexus ; S.M, Superior 
mesenteric artery and plexus; Sp, Spermatic artery and plexus; IM, Interior mesenteric artery and 
plexus ; Hy, Hypogastric nerves and plexus; Rec, Rectal plexus; Ut, Uterine plexus; Ves, Vesical 
plexus ; V.V.V, Visceral branches from sacral nerves. 
