BRANCHES OF THE INTERNAL ILIAC. 567 



Coccygeus muscles. The branches given off outside the pelvis are distributed to 

 the adjacent part of the Gluteus maximus and External rotator muscles. They 

 anastomose with branches of the sciatic artery. 



The inferior haemorrhoidal are two or three small arteries which arise from the in- 

 ternal pudic as it passes above the tuberosity of the ischium. Crossing the ischio- 

 rectal fossa, they are distributed to the muscles and integument of the anal region. 



The superficial perineal artery supplies the scrotum and muscles and integu- 

 ment of the perinseum. It arises from the internal pudic in front of the preceding 

 branches, and turns upward, crossing either over or. under the Transversus perinaei 

 muscle, and runs forward, parallel to the pubic arch, in the interspace between the 

 Accelerator urinae and Erector penis muscles, both of which it supplies, and is 

 finally distributed to the skin and dartos of the scrotum. In its passage through 

 the perinaeum it lies beneath the superficial perineal fascia. 



The transverse perineal is a small branch which arises either from the internal 

 pudic or from the superficial perineal artery as it crosses the Transversus perinaei 

 muscle. It runs transversely inward along the cutaneous surface of the Trans- 

 versus perinaei muscle, which it supplies, as well as the structures between the anus 

 and bulb of the urethra, and anastomoses with the one of the opposite side. 



The artery of the bulb is a large but very short vessel which arises from the 

 internal pudic between the two layers of the triangular ligament, and, passing 

 nearly transversely inward, between the fibres of the Compressor urethras muscle, 

 it pierces the bulb of the urethra, in which it ramifies. It gives off a small branch 

 which descends to supply Cowper's gland. 



Surgical Anatomy. This artery is of considerable importance in a surgical point of view, 

 as it is in danger of being wounded in the lateral operation of lithotomy an accident usually 

 attended in the adult with alarming hemorrhage. The vessel is sometimes very small,- occasion- 

 ally wanting, or even double. It sometimes arises from the internal pudic earlier than usual, 

 and crosses the perinseum to reach the back part of the bulb. In such a case the vessel could 

 hardly fail to be wounded in the performance of the lateral operation of lithotomy. If, on the 

 contrary, it should arise from an accessory pudic, it lies more forward than usual and is out of 

 danger in the operation. 



The artery of the corpus cavernosum, one of the- terminal branches of the 

 internal pudic, arises from that vessel while it is situated between the two layers 

 of the triangular ligament ; it pierces the superficial layer, and, entering the crus 

 penis obliquely, it runs forward in the centre of the corpus cavernosum, to which 

 its branches are distributed. 



The dorsal artery of the penis ascends between the crus and pubic symphysis, 

 and, piercing the triangular ligament, passes between the two layers of the sus- 

 pensory ligament of the penis, and runs forward on the dorsum of the penis to the 

 glans, where it divides into two branches, which supply the glans and prepuce. 

 On the dorsum of the penis it lies immediately beneath the integument, parallel 

 with the dorsal vein and the corresponding artery of the opposite side. It supplies 

 the integument and fibrous sheath of the corpus cavernosum, sending branches 

 through the sheath to anastomose with the preceding vessel. 



The Internal Pudic Artery in the Female is smaller than in the male. Its origin 

 and course are similar, and there is considerable analogy in the distribution of its 

 branches. The superficial perineal artery supplies the labia pudendi ; the artery 

 of the bulb supplies the bulbi vestibuli and the erectile tissue of the vagina; the 

 artery of the corpus cavernosum supplies the cavernous body of the clitoris ; and 

 the arteria dorsalis clitoridis supplies the dorsum of that organ, and terminates 

 in the glans and in the membranous fold corresponding to the prepuce of the 

 male. 



,The Sciatic Artery (Fig. 316), the larger of the two terminal branches of the 

 anterior trunk of the internal iliac, is distributed to the muscles at the back of the 

 pelvis. It passes down to the lower part of the great sacro-sciatic foramen behind 

 the internal pudic artery, resting on the sacral plexus of nerves and Pyriformis 



