ANATOMY IN A NUTSHELL. 565 



The penis is composed of a mass of erectile tissue enclosed in three rod-like 

 segments which are firmly united together by a sheath composed of integu- 

 ment, dartos, and fascia. These segments arc the two corpora cavernosa, and 

 the corpus spongiosum. The root of the penis is attached to the symphysis 

 and pudic arch. The body, which is triangular on cross section, forms the 

 greater part of the free portion of the organ. The glans forms the expanded 

 distal extremity of the organ and is more developed on the dorsal than on the 

 ventral aspect, and the urethral opening is at its distal extremity. The glans 

 is separated from the body by a constriction called the neck. 



The corpora cavernosa, which lie side by side, form the upper and lateral 

 parts of the penis. (Plate CCLXXIV). The crura are formed by the posterior 

 one-fourth of the corpora cavernosa, Plate CCLXXV, and are attached to the 

 tuberosities of the ischia and the descending rami of the ischia. The groove 

 above the corpora cavernosa are for the dorsal vessels and dorsal nerves, while 

 the groove below that is for the corpus spongiosum. The suspensory ligament 

 of the penis Is a fibrous membrane which connects the root of the organ to the 

 symphysis pubes. The fibrous septum between the two corpora cavernosa, 

 only present between its posterior two-thirds, is called septum pectiniform. 



The corpus spongiosum lies in the groove between the corpora cavernosa 

 inferiorly. This has no erectile tissue in it like the corpora cavernosa. It con- 

 sists of glans, a body, and a bulb. The clans is somewhat heart-shaped and 

 at its base is a ridgecalled corona glandis, behind which is the neck of the penis. 

 The external urinary meatus is a vertical fissure about one-third of an inch 

 in length at the apex of the glans. It is the outlet of the urethra. The body 

 of the corpus spongiosum has passing through its whole length the urethra. 

 For description of the urethra see page 472, and for Plate page 533. The 

 bulb of the corpus spongiosum is surrounded by the Accelerator mime mus- 

 cle. It passes posteriorly to within an inch of the anus. The prepuce is a 

 continuation of the integument of the penis which more or less completely 

 conceals the glans. The fr.enum pr.eputium is a fold of mucous membrane 

 which connects the prepuce with the glans along the raphe. Phimosis (muz- 

 zling or closure) is the tightness of the foreskin such that it cannot be drawn 

 back from over the glans. Paraphimosis is a retraction of a narrow or in- 

 flamed foreskin which cannol be replaced. Epispadias is a congenital defed 

 in which the urethra opens on the dorsum of the penis. In female epispadias 

 there is a fissure of the upper wall of the female urethra. Bypospadias i- :i 

 congenital opening of the urethra on the under side of the penis. In the female 

 hypospadias there Is an opening of the urethra in the vagina. 



The dartos is the reddish, cellular, contractile tissue beneath the skin of 

 the penis and continuous with the dartos tissue of the scrotum. The female 

 dartos is a layer of unstriped muscular fibers immediately under the skin o\ 

 the labia majora. The dartos enter- into the formation of the prepuce, and 

 some authorities claim, forms a kind of a sphincter around the preputial ori- 

 fice. The areolar tissue of the penis, which contains the superficial vessels and 

 nerves, is just beneath the dartos. (Plate CCLXXIV). The deep fascia of the 

 penis is beneath the areolar tissue. It is joined to the skin and the corpus 



