MUSCLES OF PERINEUM AND ISCHIORECTAL REGION. 229 



Insertion The dorsal interossei are inserted on the 

 inner side of the bases of first phalanges of the 

 second, third, and fourth toes, and on the outer side 

 of the bases of the second, third, and fourth toes. 

 Nerve External plantar. 



The dorsal interossei are abductors from the second 

 toe. The second toe receives the insertion of two inter- 

 osseous muscles, one on the inner, the other on the 

 outer side of the base of the phalanx. 



MUSCLES OF THE PERINEUM AND ISCHIO-RECTAL REGION. 



In the Male. 

 ACCELERATOR URIN^E. 



Origin A bipenniform muscle, from central tendon 

 of perineum in front of anus ; the tendon lies be- 

 neath the urethra, in the median line. 

 Insertion The muscular fibres curve around the ure- 

 thra, encircle the bulb, and are lost on its upper 

 surface. 



Nerve Perineal. 

 ERECTOR PENIS. 



Origin Inner border of ascending ramus of ischium 



and ramus of pubes. 

 Insertion Ends in aponeurosis, which is inserted into 



the side and under surface of crus penis. 

 Nerve Perineal. 

 TRANSVERSUS PERIN^EI. 



Origin Inner surface of tuberosity of ischium. 

 Insertion Passes inward and forward, and is inserted 

 on the central tendon of perineum just anterior to 

 the anus. 

 Nerve Perineal. 

 LEVA TOR ANI. 



Origin Attached to the inner sides of the true pelvis, 



