THE MALE EXTERNAL GENITALS. 



465 



helping to form the perineum are divided: they are the bulbocavernosus, the super- 

 ficial and deep transverse perinei, and the levator ani and external sphincter ani 

 muscles. They draw the sides of the wound apart, sometimes forming a dimple" on 

 each side, and thus enlarge the vaginal outlet and allow the anterior wall of the rectum 

 as well as the posterior wall of the bladder 

 to prolapse (Fig. 468) . 



Operation. The torn area is to be 

 denuded by beginning the incision not 

 higher up than the lower end of the labiuni 

 minus on one side and carrying it down 

 and then up to a corresponding point on 

 the opposite side. From the extremities 

 of this incision two more are made ex- 

 tending 2.5 to 5 cm. (i to 2 in.) up the 

 vagina and meeting in the median line. 

 Emmet carried the denudation up each 

 lateral sulcus. The mucous membrane so 

 marked out is then dissected away; to close 

 the wound some operators introduce and 

 bring out the stitches all on the skin surface, 

 while others introduce and tie half of them 

 on the vaginal surface and the other half on 

 the skin surface. The needle is to be car- 

 ried well out toward the rami of the ischium 

 so as to include a large mass of tissue. 



If the mucous membrane of the rectum has been torn it is to be sewed together 

 before the perineal tissues are approximated. 



FIG. 468. Rupture of the perineum. The vulva 

 gapes, showing the rectum bulging forward; the two 

 dimples, one on each side of the anus, are caused by 

 the retracted muscles. 



THE MALE EXTERNAL GENITALS. 



Penis. The penis is composed of the two corpora cavernosa attached poste- 

 riorly to the rami of the ischia and pubes and terminating in blunt ends anteriorly, 

 and the corpus spongiosum, commencing at the bulb, at the central point of the 

 perineum posteriorly, and ending in the glans anteriorly. The glans is the extended 

 corpus spongiosum and covers the ends of the corpora cavernosa. Its extended rim 



Fibrous sheat 

 Collum glandis 

 Corona glandis 



Dorsal vein 



Corpora cavernosa 



-V " - ' <'..- ':'' ?'J ',*>' 



Meatus 



Fossa navicularis 



Corpus spongiosum 



FIG. 469. Structure of the penis. 



is called the corona glandis and the groove immediately behind, the neck, or col- 

 lum glandis. In the centre of each corporus cavernosum runs an artery (Fig. 469) . 

 The skin is thin, loose, free from hair except at the root, and has beneath it 

 some fibres of the dartos. It projects over the glans, forming the prepuce and is 

 attached at the neck or collum glandis and underneath as far forward as the urethra, 

 forming thefr&num. The connective tissue beneath the skin is loose and free from 

 fat. A fibrous sheath (Buck's fascia) surrounds the corpora cavernosa and corpus 

 spongiosum and binds the three together. It is continuous posteriorly with the sus- 

 pensory ligament and the deep layer of the superficial fascia (Colles's fascia). 



30 



