INTERNAL PUDENDAL ARTERY 



613 



(1) The branches of the gluteal region are: (a) twigs to the gluteus maximus ; (6) branches 

 accompanying the nerve to the obturator internus; (c) a sacral branch which pierces the sacro- 

 tuberous hgament, and anastomoses with the inferior gluteal artery. 



(2) The inferior hemorrhoidal artery (a. hsemorrhoidalis inferior] (figs, 493, 494) arises at 

 the posterior part of the ischio-rectal fossa and, perforating the obturator fascia, at once breaks 

 up into several branches. These, running medially toward the anus, traverse the ischio-rectal 

 fat and supply the fascia, skin and the levator ani and external sphincter muscles. The in- 

 ferior haemorrhoidal branches anastomose with those from the middle and superior ha;mor- 

 rhoidal, and from the gluteal and perineal arteries. 



(3) The perineal artery [a. perinei] (figs. 493, 494), one of the terminal arteries of the in- 

 ternal pudendal, arises at the anterior part of the ischio-rectal fossa. It pierces the base of the 

 urogenital diaphragm (triangular ligament) anterior or posterior to the superficial transverse 

 perineal muscle, and enters the space deep to CoUes's fascia. Here it runs forward between the 

 ischio- and bulbo-cavernosus muscles to the scrotum or labium majus and divides into numer- 

 ous terminal branches. Immediately after piercing the diaphragm, the perineal artery gives 

 off a constant transverse perineal branch which runs toward the median hne along the super- 

 ficial transverse perineal muscle. The terminal branches of the perineal are the posterior 

 scrotal or labial arteries [aa. scrotales, or labiales posteriores] which ramify on the scrotum or 

 labia majora (according to sex) and anastomose with external pudendal arteries. 



(4) The artery of the penis, or clitoris [a. penis or clitoridis] (figs. 493, 494) pierces the free 

 border of the urogenital diaphragm and runs forward between the layers of the diaphragm 

 with the dorsal nerve of the penis along the inferior ramus of the pubis. It traverses the fibres 

 of the deep transverse perineal muscle and of the sphincter of the membranous urethra and 



Fig. 494. — The Arteries of the Male PERiN.s;trM. 



On the right side Colles's fascia has been turned back to show the perineal artery. On the 

 left side the perineal vessels have been cut away with the inferior layer of the urogenital dia- 

 phragm to show the artery of the penis. 



Posterior sacral artery 



Bulbo-cavernosus 



Colles's fascia, turned back 



Ischio-cavernosus 



Transverse perineal vessels 

 Cut edge of urogenital 

 diaphragm 

 Perineal nerve giving off 

 transverse branch 

 Internal pudendal artery — ^^_ — 



Inferior haemorrhoidal^ v\ y^^;?^ 



artery -^^ =^ "^^^' 



Gluteus maximus, 

 hooked back 



Crus penis 



Dorsal artery of penis 

 Deep artery of penis 



Artery of bulb 

 Bulbo-urethral gland 

 Artery of the penis 



Sacro-tuberous ligament 



Levator ani 



External sphincter ani 



Gluteus maximus 



ends by dividing into deep and dorsal arteries of the penis, or clitoris, according to sex. 



The branches of the artery of the penis (or clitoris) are: (o) The artery to the bulb; (6) 

 the urethral artery; and (c) the terminal, deep artery of the penis or clitoris. 



(a) The artery of the bulb [a. bulbi urethrse or vestibuli vaginse] takes a medial direction 

 through the fibres of the m. transversus perinei profundus. It then pierces the inferior fascia 

 of the urogenital diaphragm to reach the bulb, the erectile tissue of which it supphes, in either 

 sex. This vessel also supplies branches to the bulbo-urethral gland (Cowperi) or the gland of 

 the vestibule (Barthohni). 



The situation of the artery to the bulb should be remembered in performing the operation 

 of lateral lithotomy, particularly as it may arise far back. When the artery arises, as it occa- 

 sionally does, from the accessory pudendal it pierces the urogenital diaphragm further forward 

 and is out of danger in the ordinary low operation. 



(6) The urethral artery [a. urethralis] is a small branch which passes into the corpus spongi- 

 osum and anastomoses with branches from the artery of the bulb. 



