448 



THE MUSCLES AND FASCIAE 



verse perineal muscles. The region of fusion of the two leaflets is called the base. 

 The base is directed toward the rectum, and connected to the central tendinous 

 point of the perineum. It is continuous with the deep layer of the superficial 

 fascia behind the Superficial transverse perineal muscles, and with a thin fascia 

 which covers the cutaneous surface of the Levator ani muscle, the anal or ischio- 

 rectal fascia. 



.This layer of the triangular ligament is perforated, about ah inch below the 

 symphysis pubis, by the urethra, the aperture for which is circular in form; by 

 the arteries to the bulb and by the ducts of Cowper's glands close to the urethra! 

 aperture; by the arteries to the corpora cavernosa one on each side, close to the 

 pubic arch and about half-way along the attached margin of the ligament; and 

 by the dorsal arteries and nerves of the penis near the apex of the ligament. 

 Its base is also perforated by the superficial perineal vessels and nerves, while 

 between its apex and the subpubic ligament passes the dorsal vein of the penis. 



DORSAL VEIN 



OF PENIS 



DORSAL NERVE 



OF PENIS 



DORSAL ARTERY 



OF PENIS 



ARTERY TO 

 BULB 



COMPRESSOR 

 URETHRAE 



TRIANGULAR LIGAMENT 



(superficial layer) 



CORPUS 

 SPONGIOSUM 



CORPUS 

 CAVERNOSUM 

 TRIANGULAR 

 LIGAMENT 



(upper margin) 



FIG. 340. The superficial layer of the triangular ligament. The Compressor urethrae muscle lies behind the 

 superficial layer of the triangular ligament and is shown in the figure for convenience. (Poirier and Charpy.) 



When this superficial layer of the triangular ligament is detached, the following 

 structures will be seen between it and the deeper layer: The dorsal vein of the 

 penis : the membranous portion of the urethra, and the Compressor urethrae muscle ; 

 Cowper's glands and their ducts; the pudic vessels and dorsal nerve of the penis: 

 the artery and nerve of the bulb, and a plexus of veins. 



The triangular ligament in the female is not so strong as in the male. It is 

 divided in the middle line by the aperture of the vagina, with the external coat 

 of which it becomes blended; between the vaginal orifice and the pubis it is per- 

 forated by the urethra. Its base is continuous, as in the male, with the deep 

 layer of the superficial fascia surrounding the Transversus perinei muscles. Like 

 the triangular ligament in the male, it consists of two layers, between which are 

 to be found the following structures: The dorsal vein and nerves of the clitoris, a 

 portion of the urethra and the Compressor urethrae muscle, the glands of Bar- 

 tholin and their ducts, the pudic vessels, the arteries of the vestibular bulbs, 

 and a plexus of veins. The deep layer of the triangular ligament is a part of the 

 pelvic fascia, and is described on page 450. 



The Compressor or Constrictor urethrae (TO. constrictor urethrae) in the male 

 surrounds the whole length of the membranous portion of the urethra, and is 



