916 



PENIS. 



so large that it extended forwards to the middle 

 of the penis, and usurped the place of the 

 accelerator urinse, which was absent. The 

 ischio-bulhosus muscle is separated from the 

 transversus perinei by the folded border of the 

 deep and superficial perineal fasciae, and from 

 the compressor urethrae by the anterior layer 

 of the deep perineal fascia. It covers in the 

 internal pudic vessels and nerve. 



The action of the ischio-bulbosi muscles is 

 to compress the bulb, and by their pressure to 

 aid the posterior fasciculi of the acceleratores 

 urinae in producing turgescence of the corpus 

 spongiosum. In the variety to which I have 

 alluded above, the ischio-bulbosi must have 

 performed the whole of the duty of the accele- 

 ratores. 



The compressor vena dorsalis penis is a small 

 muscle, first described by Dr. Houston,* of 

 Dublin. According to that gentleman it is 

 found very commonly among mammiferous 

 animals, and also in the human subject when 

 the muscular system is well developed. To 

 its existence in the dog and cat I can bear 

 witness, having repeatedly prepared it for 

 Dr. Jones Quain, who was wont to demon- 

 strate it in his lectures ; I have been less suc- 

 cessful in the human subject, and have never 

 obtained a satisfactory view of a distinct pair 

 of muscles in the situation indicated by Dr. 

 Houston. "In man," writes this author, "the 

 compressores venae dorsalis are less distinct 

 than in most of the mammalia. They arise 

 from the rami of the pubis above the origin of 

 the erectores penis and crura, and ascending in 

 a direction forwards are inserted above the 

 vena dorsalis by joining with each other in the 

 mesian line. They form a thin stratum of 

 muscular and tendinous fibres about an inch 

 long and three quarters of an inch broad, and 

 may perhaps be looked upon as portions of the 

 erectores penis, which, instead of being inserted 

 into the sides and lower part of the corpora 

 cavernosa, mount over those bodies to exert 

 their compressing influence on the vena dor- 

 salis. They enclose between these and the 

 penis, the veins, arteries, and nerves of this 

 region. Their anterior fibres are distinguished 

 from those of the erectores by the fibrous at- 

 tachment of the crura to the pubis ; their 

 posterior margins are kept distinct from the 

 front part of the levatores ani, known under 

 the name of Wilson's muscles, by the pudic 

 artery, which divides them in its course towards 

 the dorsum of the penis." 



" The best procedure to display these mus- 

 cles is the following. Detach the bladder and 

 Jevator ani with the hand from one side of the 

 pelvis; then divide with the saw the pubis and 

 ischium about one inch from the symphysis, 

 and break off the bones at the sacro-iluc arti- 

 culation; next dissect away carefully the re- 

 maining portion of the pubis from the symphy- 

 sis, periosteum, and crura penis, and then the 

 compressores vena?, bearing still their natural 

 relations to the crura and other muscles, may 

 be exposed with very little difficulty. The 



* Dublin Hospital Reports, vol. v. page 459. 



insertion of the muscles being in a great mea- 

 sure outside the pelvis, they may also be 

 demonstrated without the section of the bones, 

 by cutting on them in front of the pubis and 

 looking carefully for their tendon at the side of 

 the vena dorsalis : from the tendon the knife 

 may be carried downwards and backwards in 

 the course of the fibres, and nearly the whole 

 of the muscle can be thereby exposed. It 

 must, however, be remembered that it will be 

 needless to search for them in a thin emaciated 

 individual, where the other muscles of the 

 perineum are so pale and soft that even they 

 can scarcely be distinguished. The subject 

 should be robust, and the muscles red, in order 

 to demonstrate them." 



Respecting the action of these muscles Dr. 

 Houston observes : " The use of the musculi 

 compressores venae is self-evident and cannot 

 be mistaken ; the effect of their contraction will 

 be to close the vein and mechanically obstruct 

 the current of blood. A simple experiment 

 will prove to demonstration that such will be 

 the necessary result of their contraction. Let 

 the muscles be stretched in the natural direction 

 of their fibres, and any fluid forced into the 

 vein will not find a passage through the vessel 

 beyond the spot where it is compressed by 

 their tendon : a very gentle pull of the muscles 

 will be sufficient to produce this effect. In 

 cases where the vein runs through the tendon 

 the pressure will be most efficacious, but even 

 in those in which the tendon is arched over the 

 vein its descent from the contraction of the 

 muscles will sufficiently compress the delicate 

 tunics of the vessel to produce the required 

 effect." 



The arteries of the penis are derived from 

 the internal pudic, itself a branch of the inter- 

 nal iliac artery. They are three in number on 

 each side ; the artery of the bulb, the artery of 

 the corpus cavernosum, and the arteria dorsalis 

 penis. 



The. arteria corporis bulbosi is given off from 

 the internal pudic at a point corresponding 

 with the level of the urethra, and passes trans- 

 versely inwards to the bulb, which it enters 

 close to the lower part of the urethra. In its 

 course inwards it lies along the upper border 

 of the transverse portion of the compressor 

 urethrae muscle, and crosses that muscle ob- 

 liquely from within outwards. It is situated 

 between the two layers of the deep perineal 

 fascia, and is surrounded by a sheath derived 

 from the anterior layer of the fascia as it enters 

 the bulb. Having entered the corpus spongi- 

 osum, the artery runs forwards in the m.dst of 

 the venous canals of that body to the glans 

 penis, in which it distributes its ultimate 

 branches. In its course the arteria bulbosi 

 gives off numerous ramuscules, which ramify 

 in the walls of the venous canals. 



T/ie arteria corporis cavcritosi is given off 

 from the internal pudic, somewhat nearer to 

 the symphysis pubis than the preceding, and 

 opposite the point of junction of the crura 

 penis; it pierces the fibrous tunic of the crus 

 penis on its inner side, to enter the structure 

 of the corpus cavernosum. In the latter it 



