600 SYMPATHETIC NERYE. 



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

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

 hypogastric plexus. 



THE LUMBAR PORTION OF THE SYMPATHETIC. 



The lumbar portion of the sympathetic is situated in ' front of the vertebral 

 column, along the inner margin of the Psoas muscle. It consists usually of four 

 ganglia, connected together by interganglionic cords. The ganglia aie of small 

 size, of a grayish color, hordeiform in shape, and placed much nearer the median 

 line than the thoracic ganglia. 



The superior and inferior branches of the lumbar ganglia serve as communicat- 

 ing branches between the chain of ganglia in this region. They are usually single, 

 and of a white color. 



The external brandies communicate with the lumbar spinal nerves. From the 

 situation of the lumbar ganglia, these branches are longer than in the other 

 regions. They are usually two in number for each ganglion, and accompany the 

 lumbar arteries around the sides of the bodies of the vertebrae, passing beneath 

 the fibrous arches from which the fibres of the Psoas muscle partly arise. 



The internal branches pass inwards, in front of the aorta, and form the lumbar 

 aortic plexus (already described). Other branches descend in front of the com- 

 mon iliac arteries, and join, over the promontory of the sacrum, to form the 

 hypogastric plexus. Numerous delicate filaments are also distributed to the 

 bodies of the vertebrae and the ligaments connecting them. 



PELVIC PORTION OF THE SYMPATHETIC. 



The pelvic portion of the sympathetic is situated in front of the sacrum, along 

 the inner side of the anterior sacral foramina. It consists of four or five small 

 ganglia on each side, connected together by interganglionic cords. Below, they 

 converge and unite on the front of the coccyx, by means of a small ganglion 

 (ganglion impar). 



The superior and inferior branches are the cords of communication between the 

 ganglia above and below. 



The external branches, exceedingly short, communicate with the sacral nerves. 

 They are two in number to each ganglion. The coccygeal nerve communicates 

 either with the last sacral or the coccygeal ganglion. 



The internal branches communicate, on the front of the sacrum, with the 

 corresponding branches from the opposite side ; some, from the first two ganglia, 

 pass to join the pelvic plexus, and others form a plexus, which accompanies the 

 middle sacral artery. 



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, from the lumbar ganglia, and from the first two sacral 

 ganglia. This plexus contains no ganglia, and bifurcates, below, into two lateral 

 portions, which form the inferior hypogastric or pelvic plexuses. 



INFERIOR HYPOGASTRIC OR PELVIC PLEXUS. 



The inferior hypogastric or pelvic plexus is situated at the side of the rectum 

 and bladder in the male, and at the side of the rectum, vagina, and bladder, 

 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 sacral ganglia. At the point of junction of these nerves, small ganglia 

 nre found. From this plexus numerous branches are distributed to all the viscera 

 of the pelvis. They accompany the branches of the internal iliac artery. 



