THE PENIS 



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penis, extending farther on their upper than on their lower surfaces. At the summit 

 of the glans is the slit-like vertical external urethral orifice. The circumference 

 of the base of the glans forms a rounded projecting border, the corona glandis, 

 overhanging a deep retroglandular sulcus, behind which is the neck of the penis. 



For descriptive purposes it is convenient to divide the penis into three regions : 

 the root, the body, and the extremity. 



-^ 



Prostatic portion 

 of urethra. 

 Ejnndatory duct. 



/ 



SPHINCTER AMI. ' ' 



Prostatic plexus* 

 of veins. 



land 



>?/// .Fossa 



'navicularis. 



Prepuce. 



FIG. 1156. Vertical section of bladder, penis, and urethra. 



The root (radix penis) of the penis is triradiate in form, consisting of the 

 diverging crura, one on either side, and the median urethral bulb. Each crus 

 is covered by the Ischiocavernosus, while the bulb is surrounded by the Bulbo- 

 cavernosus. The root of the penis lies in the perineum between the inferior fascia 

 of the urogenital diaphragm and the fascia of Colles. In addition to being attached 

 to the fasciae and the pubic rami, it is bound to the front of the symphysis pubis 

 by the fundiform and suspensory ligaments. The fundiform ligament springs from 

 the front of the sheath of the Rectus abdominis and the linea alba; it splits into two 

 fasciculi which encircle the root of the penis. The upper fibers of the suspensory 

 ligament pass downward from the lower end of the linea alba, and the lower fibers 

 from the symphysis pubis; together they form a strong fibrous band, which extends 

 to the upper surface of the root, where it blends with the fascial sheath of the organ. 



The body (corpus penis) extends from the root to the ends of the corpora caver- 

 nosa penis, and in it these corpora cavernosa are intimately bound to one another. 

 A shallow groove which marks their junction on the upper surface lodges the 

 deep dorsal vein of the penis, while a deeper and wider groove between them 

 on the under surface contains the corpus cavernosum urethrse. The body is 

 ensheathed by fascia, which is continuous above with the fascia of Scarpa, and 

 below with the dartos tunic of the scrotum and the fascia of Colles. 

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