I970 



HUMAN ANATOMY. 



Central blood-spaces 



Fig. 1678. 



Inner peripheral spaces 



Outer peripheral spaces 



more superficially situated venous trunks, as the dorsal vein, arise chiefly from the 

 venous net-works of the peripheral zone. The veins possess an unusually well- 

 developed muscular coat, and in places exhibit local cushion-like thickenings of their 

 intima similar to but less marked than those seen in the arteries. 



Vessels. — The arteries of the penis constitute a superficial and a deep set, the 

 former supplying the integument and associated envelopes, while the latter convey 

 blood to the masses of erectile tissue. The superficial arteries include twigs from 

 the external pudic branches of the femorals to the lateral and under surface of the 

 penis, from the dorsal arteries to the anterior surface and the prepuce, and from the 

 superficial perineals by small vessels to the posterior part of the urethral surface. 

 The deep arteries — all branches from the internal pudics — supply the three cylinders 

 of erectile tissue, including the glans. The corpus spongiosum receives the arteries 

 of the bulb, their continuations (sometimes described as the urethral arteries) accom- 

 panying the urinary canal as far as the glans, where they anastomose with the terminal 

 branches of the dorsal arteries. The last-named vessels also send small twigs around 

 the corpora cavernosa to the spongy body. The corpora cavernosa are supplied 

 chiefly by the deep arteries of the penis, supplemented by twigs from the dorsal 



arteries that pierce the albu- 

 ginea. Entering the cavern- 

 ous bodies about where the 

 crura unite, the deep arteries 

 of the penis traverse the cyl- 

 inders somewhat eccentri- 

 cally, to the median side of 

 their axes. Communication 

 between the vessels of the 

 two bodies is established by 

 anastomotic twigs that pass 

 through the apertures in the 

 median septum, as well as 

 by the terminal loop. The 

 dorsal arteries, the longest 

 branches of the internal 

 pudics, pass along the dor- 

 sum between the fascia and 

 the albuginea, in company 

 with the dorsal nerves and 

 vein, and, in addition to the 

 twigs distributed to the cov- 

 erings, the cavernous bodies, 

 and the corpus spongiosum, 

 supply the erectile tissue of 

 the glans. The anastomoses 

 between the various vessels 

 supplying the penis are very free, not only between the corresponding and other 

 branches of the two sides, but also between those of the superficial and deep sets. 



The veins of the penis, like the arteries, constitute a superficial and a deep 

 group which freely communicate and carry of? the blood from the envelopes and from 

 the erectile tissue respectively. The superficial veins for the most part are tributary 

 to a subcutaneous trunk (v. dorsalis penis superficialis) that passes upward along the 

 dorsum beneath the skin to the pubes and terminates either by di\'iding into branches 

 that empty into the internal saphenous or the femoral veins on either side or by 

 joining the deep dorsal vein ; both modes of ending, however, may exist. A number 

 of vessels from the integument covering the posterior part of the urethral surface are 

 collected by the anterior scrotal veins. 



The deep veins, which begin by tributaries from the erectile tissue that they 

 drain, to a large extent discharge their contents into the deep dorsal vein (v. dorsalis 

 penis profunda ) that lies beneath the fascia and occupies the groove on the dorsum 

 as far as the suspensory ligament, between the superficial and deep parts of which it 



Trabeculae 



Bundles of muscle 



Dense fibrous tissue of 

 tunica albuginea 



Transverse section through periphery of corpus cavernosum. X 50. 



