200 MUSCLES OF THE PERINEUM. 



In the female this muscle is inserted into the coccyx and fibrous 

 raphe, extremity of the rectum and vagina. 



Relations. By its external or perinea! surface, with a thin layer 

 of fascia, by which, and by the obturator fascia it is separated from 

 the obturator internus muscle ; with the fat in the ischio-rectal fossa, 

 the deep perineal fascia, the levator ani, and posteriorly with the 

 gluteus maximus. By its internal or pettic surface with the pelvic 

 fascia, which separates it from the viscera of the pelvis and peri- 

 toneum. 



The Coccygeus muscle is a tendino-mus*cular layer of a triangular 

 form. It arises from the spine of the ischiunv and is inserted into 

 the side of the coccyx and lower part of the sacrum. 



Relations. By its internal or pelvic surface, with 'the Vecum l ;My^ 

 its external surface with the lesser and greater sacro-ischiatic liga- 

 ments. 



The muscles of the perineum in the female are the same as in the 

 male, and have received analogous names. They are smaller in 

 size, and are modified to suit the different form of the organs ; they 

 are 



Constrictor vagifiae, 

 Erector clitoridis, 

 Transversus perinei, 

 Compressor urethras, 

 Sphincter ani, 

 Levator ani, 

 Coccygeus. 



The Constrictor vagina is analogous to the acceleratores urinae ; 

 it is continuous posteriorly with the sphincter ani, interlacing with 

 its fibres, and is inserted anteriorly into the sides of the corpora 

 cavernosa, and fascia of the clitoris. ? 



The Transversus perinei is inserted into the side of the constrictor 

 vaginae, and the levator ani into the side of the vagina. 



The other muscles are precisely similar in their attachments to 

 those in the male. 



Actions. TJie acceleratores urinae being continuous at the middle 

 line, and attached on each side to the bone, by means of their pos- 

 terior fibres will support the bulbous portion of the urethra, and act- 

 ing suddenly will propel the semen, or the last drops of urine from 

 the canal. The posterior and --middle fibres, according to Krause,* 

 contribute towards the erection of the corpus spongiosum, by pro- 

 ducing compression upon the venous structure of the bulb ; and the 

 anterior fibres, according to^yrrell,! assist in the erection of the 

 entire organ by compressing jthe vena dorsalis, by means of their 



insertion into the fascia penis^The erector penis becomes entitled 



' 



* Mailer, Archiv fur Anatomic, Physiologic, &c. 1837, 

 t Lectures in the College of Surgeons. 1839. 



