388 HUMAN ANATOMY. 



It helps with its fellow to form the floor of the pelvis, and 

 supports the vagina, rectum, and pelvic viscera. Nerves, infe- 

 rior haemorrhoidal and fourth sacral. 



COCCYGEUS MUSCLE (coccygei), from the spine of the 

 ischium and lesser sacro-sciatic ligament, and is inserted into 

 the margin of coccyx and side of lowest segment of sacrum. It 

 raises the coccyx and forms the posterior part of the pelvic floor. 

 Nerve, anterior division of the fifth sacral. 



The muscles of the female perineum are: 



Superficial Set. 



Sphincter vaginae, or bulbo-cavernosus ; 



Erector clitoridis ; 



Transversus perinaei; 



Sphincter ani; 



Levator ani; 



Coccygeus. 



Deep Set. 



Transversus perinaei (deep) ; 



Constrictor vaginae; 



Depressor urethrae, or Jarjavay's muscle. 



The structures beneath the deep layer of the superficial 

 fascia are : 



Erector penis muscle; 



Accelerator urinae muscle; 



Transversus perinaei muscle and arteries ; 



Superficial perineal vessels. 



The structures between the two layers of the deep perineal 

 fascia are : 



Compressor urethrae muscle; 



Membranous urethra ; 



Subpubic ligament; 



Dorsal vein of penis ; 



Pudic vessels and nerves; 



Venous plexus ; 



Cowper's glands and ducts; 



Arteries and nerves of bulb. 



ANATOMY OF LATERAL LITHOTOMY. 



The incision is made through a triangular interval formed 

 by the transversus perinaei, accelerator urinae, and erector penis 

 muscles, and divides the following structures in the order 

 named : 



Skin and superficial fascia; 



