NERVOUS SYSTEM. 351 



derable branch — the spermaticus externiis, which passes through 

 the abdominal ring, and sends twigs, in the male, to the scrotum, 

 and a filament along the chord to the testicle ; in the female, 

 filaments go from it to the uterus, udder, and external labia. 



The third nerve is almost wholly consumed in forming the 

 crural nerve. It sends a small branch to the sympathetic, ano- 

 ther to the psoas, and a third backward to the obturator nerve. 



The Jour th nerve detaches a filament of communication to the 

 .-sympathetic, and then joins the others in contributing to the pro- 

 duction of the crural nerve ; but, in addition, it sends a considera- 

 ble branch to the obturator nerve. 



Thejifth nerve communicates with the sympathetic, and after- 

 wards subdivides into three considerable branches : one assists in 

 the formation of the crural; another joins the obturator; and a 

 third splits and sends one portion to the gluteal, but a much 

 larger one to the sciatic nerve. 



SACRAL NERVES. 



Of these nerves we reckon five pairs. The foremost nerves are 

 of very large size; the two last are much diminished in volume : 

 they all take an oblique direction backward, and traverse the la- 

 teral parietes of the pelvis. 



To facilitate their description, we may consider these nerves 

 also as consisting of superior and inferior fasces. 



The superior fasces make their e.xit through distinct fora- 

 mina upon the upper part of the sacrum, and are there buried 

 under a thick mass of muscle : a few filaments from them pierce 

 the faschia above and become subcutaneous, and ramify upon the 

 outer part of the haunch. 



The inferior fasces, remarktrble for their large size, are of 

 more importance. The frst nerve largely contributes to the ori- 

 gin of the sciatic ; but it also sends a considerable branch to the 

 gluteal nerve. It communicates with the sympathetic and second 

 lumbar nerve. 



The second nerve communicates with the third and sympathetic, 

 and afterwards sends off two large branches. One joins the 

 sciatic ; the other continues backward, and disappears among the 

 coccygeal muscles. 



The third nerve has similar connexions, and likewise joins the 

 sciatic; but the major part runs backward, along the side of the 

 pelvis, and penetrates the muscles of the haunch. 



The fourth nerve, similarly connected, is principally destined 

 to the supply of the bladder and rectum, and muscles of the anal 

 region . 



