THE PENIS. 



1299 



jived into a hollow in the base of the glans. The skin covering the body of 

 the penis is thin, delicate, and freely movable, and, except near the root of the 

 organ, is free from hairs ; on the urethral aspect of the penis the skin is marked 

 by a median raphe, continuous with the raphe of the scrotum. Traced towards 

 the base of the glans, the skin forms a free fold called the prseputhim, or prepuce, 

 which overlaps the glans to a variable extent. From the deep surface of the 

 prepuce the skin is reflected on to the terminal' part of the penis, along a line just 

 proximal to the corona glandis, and is continued over the entire glans to the 

 external urethral orifice. A small median fold, the frenulum prseputii, passes to the 

 deep surface of the prepuce from a point immediately below the orificium urethrse 

 externurn. The skin covering the glans is firmly attached to the underlying 

 erectile tissue, and here, as well as on the deep surface of the prepuce, it presents 

 some resemblance to mucous membrane. 



Sometimes minute sebaceous glands, glandulse praeputiales, are found in very variable 

 numbers on the glans and inner surface of the prepuce ; the secretion from these when 

 they are present may help to form the smegma prseputii, which tends to collect in the 

 groove between the glans and the prepuce. The main source of the smegma is to be 

 found in the desquamated and broken-down epithelial cells derived from the surface of 

 the glans and prepuce. 



At the radix penis, or root, the three component parts of the organ separate 

 from one another (Fig. 1018). 

 The corpora cavernosa 

 penis, diverging from 

 each other laterally, at first 

 become somewhat swollen, 

 and then, gradually tapering, 

 gain a firm, fibrous attach- 

 ment to the periosteum on the 

 medial surface of the pubic 

 arch. These diverging parts 

 of the corpora cavernosa are 

 called the crura penis, and 

 each is covered by the cor- 

 responding ischio-cavernosus 

 muscle. The corpus caver- 

 nosum urethrse lying between 

 the crura becomes enlarged, 

 and forms a somewhat spheri- 

 cal mass which receives the 

 name bulbus urethrse. The 

 bulb varies much in size in 

 different individuals, and is 



ittached to the under sur- p IG . 1018. STRUCTURES COMPOSING THE RADIX PENIS. 



face of the fascia inferior of The corpus penis is seen in section. 



the urogenital diaphragm, 



against which it rests. , The posterior part and under surface of the bulb usually 

 show a median notch or groove an indication that the bulb is originally composed 

 of two symmetrical portions, which during development have become fused in the 

 median plane. These two portions are termed the hemispheria bulbi urethrse, and 

 are best seen in subjects whose tissues have been hardened by in tra vascular 

 injection. A slightly marked median septum, situated within the bulb tissue, 

 indicates on a deeper plane the line along which fusion has taken place. The 

 canal of the urethra, piercing the fascia inferior of the urogenital diaphragm, enters 

 the bulb obliquely a short distance in front of its posterior extremity (Fig. 1024). 

 Covering the superficial surface of the bulb is the bulbo-cavernosus muscle. 



A somewhat triangular band of strong fibrous tissue, called the ligamentum 

 suspensorium penis, is attached to the front of the symphysis pubis, and extends 

 to the fibrous capsule of the penis, with which it becomes continuous (Fig. 1017). 



83 a 



Corpus caver- 

 -nosum penis 



Urethra 



Corpus i caver- 



nosum urethrae 



Bulb of urethra 

 [ Inferior fascia of 

 j urogenital diaphragm 

 Corpus cavernosum penis 



