740 



THE NEEVOUS SYSTEM. 



Coursing forwards through the anterior part of the ischio-rectal fossa, it passes 

 between the two layers of fascia of the urogenital diaphragm towards the urethra. 

 It supplies muscular branches to the anterior parts of the levator ani and external 

 sphincter, to the transversus perinei superficialis and profundus, ischio-cavernosus, 

 bulbo-cavernosus (or sphincter vaginse), and sphincter urethrse membranacese. It 

 terminates as the nerve to the bulb, which, piercing the urogenital diaphragm, 

 enters the bulb of the urethra and supplies the erectile tissue of the bulb and 

 corpus cavernosum urethrae, as well as the mucous membrane of the urethra as far 

 as the glans penis. 



N. Dorsalis Penis vel Clitoridis. The dorsal nerve of the penis or clitoris, 

 the other terminal branch of the pudendal nerve, accompanies the internal pudendal 

 artery above the fascia inferior of the urogenital diaphragm. It passes forward 

 close to the pubic arch, lying under cover of the crus and ischio-cavernosus and 

 fascia inferior of the urogenital diaphragm, and upon the sphincter urethrae mem- 

 branacese muscle ; piercing the fascia inferior of the urogenital diaphragm near 



Nerve to obturator interims --T- 



Puclendal nerve 



Lumbo-sacral trunk 



_ The anterior rami 



^of the first four 

 sacral nerves 



TTT-- Pudendal nerve 



Perineal branch of 

 the fourth sacral 

 nerve 

 .Inferior 

 haemorrhoidal 



Perineal branch 

 of pudendal nerve 

 Deep perineal nerve 



Superficial perineal nerve 

 FIG. 633. THE ORIGIN AND COURSE OF THE PUDENDAL NERVE. 





its apex, at the lateral side of the dorsal artery of the penis (or clitoris), it passes 

 on to the dorsum of the penis or clitoris, to which it is distributed in its distal 

 two-thirds, sending branches round the sides of the organ to reach its under surface. 

 In the female the nerve is much smaller than in the male. The dorsal nerve of 

 the penis supplies one branch, the nerve to the corpus cavernosum penis, as it lies 

 between the fasciae of the urogenital diaphragm. This is a slender nerve, which, 

 piercing the fascia inferior of the urogenital diaphragm, supplies the erectile tissue 

 of the crus and corpus cavernosum penis. 



Morphology of the Pudendal Plexus. The structures occupying the perineum are placed 

 in the ventral axis of the body, and comprise, from before backwards, the penis and scrotum, or 

 mons Yeneris and vulva, the central point of the perineum, the anus and ischio-rectal fossa, and 

 the coccyx. They are placed on the medial side of the attachment of the lower limbs the penis 

 or mons Veneris in relation to the preaxial border ; the coccyx in relation to the postaxial border 

 of the limb. 



The nerves of the perineum, thus reaching the ventral axis of the trunk, are homologous with 

 the anterior (ventral) terminations of other nerves. They are separable into two series. The 

 perineum is supplied mainly through the pudendal plexus by the last four sacral and the coccygeal 

 nerves, but it is also innervated to a minor extent by the first lumbar nerve through the ilio- 

 inguinal nerve, which reaches the root of the penis and the scrotum. The region is thus 

 supplied by two series of widely separated nerves, which have their meeting-place on the 

 dorsum and side of the penis and scrotum. This junction of the ilio-inguinal and pudendal 

 nerves constitutes the beginning of the ventral axial line, which extends peripherally along 



