780 



SURGICAL ANATOMY OF THE PERINEUM. 



In the lateral operation of lithotomy, the knife is carried obliquely across the 

 back part of this space, downwards and outwards, into the ischio-rectal fossa, 

 dividing the Transversus perinei muscle and artery^ the posterior fibres of the 

 Accelerator urinas, the superficial perineal vessels and nerve, and, more posteriorly, 

 the external hemorrhoidal vessels. 



The superficial and transverse perineal arteries are described at p. 434 and 

 the superficial perineal and inferior pudendal nerves, at pp. 586, 588. 



The Accelerator urinse and Erector penis muscles should now be removed, when the deep 

 perineal fascia will be exposed, stretching across the front part of the outlet of the pelvis. The 

 urethra is seen perforating its centre, just behind the bulb ; and on either side is the crus penis, 

 connecting the corpus cavernosum with the ramus of the ischium and pubes. 



Fig. 392. Deep Perineal Fnscia. On the left side, the anterior layer 

 lias been removed. 



Anterior Layer ef 

 Dtt-p. Perineal fascia Ts- 

 Shelving 



Jnlrmal Pud U Art V. 

 ty vftkcBu.lt 

 wcfe Gland 



The muscles of the perineum in the female are the 



Sphincter vaginas. Compressor urethras. 



Erector clitoridis. Sphincter ani. 



Transversus perinei. Levator ani. 

 Coccygeus. 



The Sphincter Vaginse surrounds the orifice of the vagina, and is analogous to 

 the Accelerator urinas in the male. It is attached, posteriorly, to the central 

 tendon of the perineum, where it blends with the Sphincter ani. Its fibres pass 

 forwards on each side of the vagina, to be inserted into the corpora cavernosa and 

 body of the clitoris. 



The Erector Clitoridis resembles the Erector penis in the male, but is smaller 

 than it. 



The Transversus Perinei is inserted into the side of the Sphincter vaginas, and 



