680 MUSCLES OP THE PERINEUM. 



descend along the side of the lower fundus of the bladder, 

 the membranous part of the urethra, and the prostate 

 gland, are inserted into the central point of the perineum. 

 The middle fibres are inserted, according to Dr. Horner, 

 into the semicircumference of the rectum, between the lon- 

 gitudinal fibres of the latter and the circular fibres of the 

 sphincter ani, while the posterior fibres are inserted into 

 the os-coccygis and back part of the rectum. 



Function. To draw the rectum forward and assist in ex- 

 pelling the fasces, urine, and semen. 



The compress ores or levatores urethra, described by Mr. 

 Wilson, and the transverse compressors of Mr. Guthrie, are 

 regarded as nothing more than the anterior portions of the 

 levator ani. 



In the female perineum, the erector ditoridis muscle cor- 

 responds with the erector penis, and the sphincter vaginae, 

 with the accelerator urince. 



Blood-vessels of the perineum. The arteries come from 

 the internal pudic, and consist of, 1. Inferior hcemorrlioidal, 

 going to the side of rectum and anus. 2. Superficial peri- 

 neal. 3. Transverse perineal. These two latter supply the 

 perineal space and go to the scrotum. 4. Artery of the bulb, 

 which passes between the layers of the triangular ligament 

 and goes to the bulb and corpus spongiosum. The veins 

 corresponding to the arteries terminate in the internal 

 iliac vein. 



Nerves of the Perineum.^-These come from the pudic 

 nerve, which arises from the lower part of the sacral plexus 

 and takes the course of the internal pudic artery. The in- 

 ferior branch of the pudic is the proper perineal nerve, and 

 gives off the external perineal, superficial perineal, and nerve 

 of the bulb. 



