THE PENIS 



1033 



attached to the iscliio-jnibic rami; and tlie distal end, pointed somewhat lik(i the 

 tip of a cigar, is plunged into the substance of the glans (tig. G28). The entire 

 length of the corpus eavernosum averages about six inches, and its Ijreadth about 

 half an inch, l)ut it increases in size i)y one-third or more when its vascular spaces 

 are fully distended. 



In structure it consists of a sponge-like erectile tissue invested by a strong sheath 

 or tunica albuginea. The sheath is about a line in thickness, white, remarkably 

 tough, and consists of two laminie, an external, of longitudinal lil)r('s common to 

 both corpora cavernosa; and an internal, of circular fibres surrounding each corjnis 

 and forming a mesial septum pectiniforme where ttie two corpora cavernosa come 

 into contact. The framework of the cavernous structure is formed by a reticular 

 arrangement of tibro-nmscular trabecular bands, starting from the inner surface of 

 tbe all)Uginea and becoming more slender as they approach the axis of the body. 

 The branches of the supplying artery run in the trabecule and terminate by open- 

 ing into the anastomosing intertral)ecular spaces which represent the widely dilated 

 capillaries of the organ. 



The corpus spongiosum lies in the middle line and below the united corpora 

 cavernosa. Unlike the latter it has no direct attachment to the ])elvic l)ones, but 

 terminates at each end in a l>ulbous expansion. It may be divided into a glans, a 

 l)ody, and a bulb. 



The anterior enlargement, or glans, is somewhat heart-shaped, its l>ase extend- 

 ing much farther over the dorsal than over the ventral asi)eet of the corpora caver- 



FiG. 628.— Transverse Section of the Penis through the Base of the Glans. 



CORPUS SPONGIOSUM (GUNS) 



DISTAL EXTREMITY OF CORPUS 

 CAVERNOSUM 



CORPUS SPONGIOSUM Integument 



nosa, and showing a distinct indication of division into two lateral lobes in the latter 

 situation. The most prominent i)art of the base is called the corona glandis, and 

 the groove behind this is the neck of the penis or balano-preputial furrow. At its 

 tip it presents a vertical fissure about one-third of an inch in length, the external 

 urinary meatus or outlet of the urethra. 



The glans is composed of erectile tissue with coarse tral)ecula^, and is covered 

 with a firmly adherent layer of skin continuous Avith the inner layer of the prepuce. 

 Its cajiacity for vascular engorgement is much less than that of the cor])Us eaverno- 

 sum or the rest of the corpus spongiosum, and it does not attain a like degree of 

 hardness during erection. 



The structural continuity of the glans with tbe cori)US spongiosum is })ro])al)ly 

 not morphological. The recent investigations of Retterer indicate that the greater 

 I)ortion of the glans is developed sejjarately as a part of the cutaneous and fibrous 

 envelope of the penis, and becomes erectile as a later change. 



The body of the corpus spongiosum is cylindrical, uniform in diameter, and 

 traversed axially in its whole length by the urethra ; it is lodged above in a groove 

 Ix'tween the two corj)ora caviM'nosa, while its ventral aspect is subcutaneous except 

 where it corresponds t<i the attachment of the scrotum. .Structurally it is provided 

 with a thin albuginea, between which and tlie urethra lies a narrow layer of erectile 

 tissue. 



The bulb is fi^rmed l)y an expansion of the erectile structure, and the jjortion 

 of the urethra bv which it is traversed undergoes a well-marked dilatation, and lies 



