THE LUMBO-SACBAL PLEXUS. 



779 



external genital organs, are represented in Solipeds by the ramifications of the lumbar 

 nerves, which have been separately described. The terminal branches are the 

 obturator crural, and anterior femural (or anterior crural). There is nothing to be said 

 respecting the obturator nerve ; 



FiV. 358. 



it Ictives the pelvis by the obtura- 

 tor foramen, as iu all the animals 

 mentioned. The crural has 

 been described as having four 

 terminal branches : the internal 

 and external musculo-cutaneous, 

 the nerve of the triceps crureus 

 (muscular hrancli), and the m- 

 ternal saphenous. The two mus- 

 culo-cutaneous branches have 

 their analogue in the Horse, in 

 the filament we have named the 

 accessory branch of the internal 

 saphenous. The nerve of tlie 

 triceps is expended in the an- 

 terior rectus, and the vastuo 

 intemus and extemus. Tlie 

 saphenous defcends between the 

 muscles of the inner aspect of 

 the thigh, beneath the aponeu- 

 rosis, aud becomes superficial at 

 a short distance from the con- 

 dyle of the femur, giving a 

 patellar branch that divides in 

 the skin of the knee, and a 

 tibial branch that is expended 

 on the inner face of the tarsal 

 articulations and the foot. 



The sacral plexus comprises 

 the first three sacral nerves, t > 

 which is added a luriibo-sacral 

 branch furnished by the lumbar 

 nerves, and a fine filament that 

 ascends from the fourth sacral. 



Ten collaterals ami a ter- 

 minal branch urise from this 

 plexus. 



The collateral branches are 

 divided into intrapelvic and 

 extrapelvic: they are five iu 

 each group. The first are des- 

 tined to the muscles of the inner 

 aspect of the pelvis, and tn those 

 of the perineum and t e skin 

 of this region. The second are 

 distributed to the muscles on 

 the outer aspect of the pelvis, 

 and the sltin on the posterior face of the thitrh. They are : 



1. Visceral branches that descend on the sides of the rectum and are lost in the 

 hypogastric plexus ; 2, Nerve of the elevator of the anus ; 3, Hirmorrhuidal or anal nerve ; 

 4, Nerve of the internal obturator that appears to arise, in the Horse, from the sciatic 

 trunk; 5, Internal pudic, which has been described with the sacral nerves. In Man this 

 nerve leaves the pelvis by the grt at sciatic notch (or foramenj, and returns to it by the 

 lesser ; within the ischiatic tubei osity it divides into two branches : an inferior or 

 perineal, and a superior or dorsalis penis nerve. The latter is placed on the dorsum 

 of the penis, and reaches the mucous membrane of the glans and prepuce; the former 

 does not go beyond the muscles and integuments of the perineum. 6, The superior 

 gluteal nerve ; 1, Nerve of the pyramidalis , 8, Nerve of the superior gemellus ; 9, Nerve of 

 the inferior gemellus and quadratus eruralis ,10, The smaU sciatic, or inferior gluteal nerve, 

 the inferior or femoral branch of which is very long, descending, as it does, to the middle 

 of the posterior face of the thigh, beneath the crural aponeurosis, to the popliteal space, 

 where it becomes superficiLiI, and terminates in the skin of the upper portion of the leg. 



LUMBAR PLtXUS OF MAN 



1, Eight gangliated cord of sympathetic ; 2, Abdominal 

 aorta ; 3, 3, Last dorsal nerves ; 4, Psoas parvus ; 5, 

 Quadi-atus lumborum ; 6, Psoas magnus ; 7, 7, Ilio- 

 hypogastric nerves ; 8, Iliacus internus ; 9, 9, Ilio- 

 inguinal nerve ; 10, Lumbo-sacral nerve ; 11, Genito- 

 crural nerve ; 12, Gluteal nerve ; 13, Iliac branch of 

 ilio-hypogastric nerve ; 14, Sacral plexus ; 15, 15, 15, 

 External cutaneous nerves ; 17, Transversalis abdomi- 

 nis ; 19, Obliquus internus; 21, Obliquus externus ; 

 23, 23, Anterior crural nerves ; 25, 25, Obturator 

 nerves ; 27, 27, Crural branch of genito-crural nerve ; 

 29, Genital branch of genito-crural nerve ; 31, External 

 iliac artery ; 33, External abdominal ring. 



