THE ABDOMEN 625 



vesical arter^^ Its course is forwards along th^side of the bladder, then 

 along the side of the prostate gland to the triangular ligament of the urethra, 

 which it pierces above the membranous part of the canal, and so reaches the 

 root of the penis. The accessory pudic furnishes the artery of the corpus 

 cavemosum and the dorsal arter>' of the penis, and in some cases the artery 

 of the bulb. 



2. Artery ol the Corpus Spongiosum (Artery of the Bulb). — Sometimes two 

 arteries are present on one side ; sometimes the artery is absent on one side ; 

 and sometinies it is of very small size. A much more important variety of this 

 artery affects its origin. It may arise from the fourth part of the internal 

 pudic close to the base of the triangular ligament, and even from the third 

 part at the front of the ischio-rectal fossa. In these cases the artery cannot 

 escape division in the operation of lateral lithotomy. In other <:ases it may 

 arise from an accessory pudic artery, when it will lie higher up and further 

 forwards than usual. 



3. Dorsal Artery of the Penis. — This vessel may arise from the obturator 

 artery in the obturator canal, or from one of the external pudic branches of 

 the common femoral artery. 



Veins. — Lying in each compressor urethrje muscle there is a plexus 

 of veins, which receives its tributaries from the corresponding corpus 

 cavemosum and one half of the corpus spongiosum and bulb. The 

 internal pudic venae comites arise on either side from this plexus, 

 and accompany the internal pudic artery as far back as the upper 

 border of the spine of the ischium, one lying on either side of the 

 vessel. Here they join to form one trunk, which enters the pelvis 

 through the lower compartment of the great sacro-sciatic foramen, 

 and terminates in the internal iliac vein. They receive as tribu- 

 taries the transverse perineal, superficial perineal, and inferior 

 hemorrhoidal veins, as well as a few veins from the gluteus maximus 

 and external rotator muscles. The inferior hemorrhoidal veins 

 take their origin in a plexus of veins which is situated on the outer 

 surface of the external sphincter muscle. Having crossed the 

 ischio-rectal fossa through its loose fat, and being ultimately reduced 

 to two or three in number, they join the internal pudic venae comites. 



It is to be noted that, though there are two dorsal arteries, 

 there is only one dorsal vein, which takes the following course : 

 after leaving the dorsum of the penis it passes through an opening 

 between the subpubic and transverse pelvic or perineal ligaments, 

 where it communicates on either side with the venous plexus in 

 each half of the compressor urethfae muscle. Haxang entered the 

 cavity of the pelvis, it divides into two branches, right and left, 

 which join the prostatic plexus of veins. 



Lymphatics. — ^The superficial lymphatics of the perineum, as well 

 as those of the anus and lower part of the anal canal, pass to the 

 inguinal glands, which lie inunediately below Poupart's ligament, 

 whilst the deep lymphatics pass to the internal iliac glands. 



Pudic Nerve. — ^The pudic nerve is one of the terminal branches 

 of the sacral plexus, and derives its fibres from the ventral division 

 of the second, the lower branch of the third, and the upper branch 

 of the fourth sacral nerves, the majority of its fibres being derived 

 from the lower branch of the third. Leaving the pelvis through 

 the lower compartment of the great sacro-sciatic foramen, the nerve 



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