1034 



THE MALE REPRODUCTIVE ORGANS 



nearer its upper than its lower surface. It is about an inch and a half in length, 

 and its greatest width is about three-quarters of an inch. It is surrounded by the 

 bulbo-cavernosi muscles, the greater part of the filjres of Avhich pass between it and 

 the corpora cavernosa to blend together in the middle line ; and it rests posteriorly 

 ngainst the superficial triangular ligament about half an inch in front of the anus. 

 It is liable to considerable enlargement after middle age. 



Muscles. — The muscles of the penis arc three on each side — the ischio- 

 cavernosus, the bull)o-cavernosus, and the superficial transversus perinaei (fig. 629). 



The ischio-cavernosus (erector penis) arises from the inner surface of the 

 tuberosity and ramus of the is(?hium, from the pubic ramus, and from the adjacent 

 root of the crus penis, and is inserted into the surface of the tunica albuginea of 



Fig. 629. — The Male Perix.eum. (Modified from Hirschfeld and Leveille.) 



BULBO-CAVERNOSUS 



Superfloial triangular ligament 



ISCHIO-CAVERNOSUS 



Muscles of thigh 



INFEBIOR PUDESDAL NER\ 

 SUPERFICIAL PERINEAL NERVE 



INFERIOR HEMORRHOIDAL NERVE 

 CUTANEOUS BRANCH OF FOURTH SACRAL 



Gluteus maximuB 



TUBEROSITY OF ISCHIUM 

 Great sacro-seiatie ligament 

 Levator ani 

 Superficial transversus perinaei 



Sphincter ani 



the corpus cavernosum near the point of attachment of the suspensory ligament. 

 A slip, the compressor venae dorsalis, is occasionally detached from its more 

 distal portion, and becomes inserted into the fascial sheath of the penis over the 

 dorsal vessels, or may l)lend with its fellow in a narrow tendon in this situation. 



The bulbo-cavernosus (accelerator urinae) arises from a median raphe 

 which extends froin tlie anterior extremity of the sphincter ani along the whole 

 length of the bulb as far as the level of the symphysis. A few of its more posterior 

 fibres pass outwards to become inserted into the superficial triangular ligament and 

 into the bulb, and a bundle of its most anterior fibres, muscle of Houston, may, 

 like the similar sli]) from the ischio-cavernosus, form a sling around the corpora 

 cavernosa and become attached to the fascial sheath of the penis, or it may be 

 inserted into the side of the corpus cavernosum itself. In the former case it acts as 



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