ANATOMY IN A NUTSHELL. 



491 



into the sides of the rectum blending with the fibers of the sphincter muscles. 

 (3) The anterior fibers, which are the longest, descend upon the side of the 

 prostate gland to join beneath it with fibers of the opposite side, and also blend- 

 ing with fibers of the External sphincter and Transversus perinaei a1 the central 

 tendon. 



Action. — It is a muscle of forced expiration. It also supports the Lower 

 end of the rectum, vagina, and bladder during efforts of expulsion. 



Nerve Supply. — Branch from the anterior division of the fourth sacral 

 and a branch from fhe pudic nerve which sometimes comes from the perineal 

 or from the inferior hemorrhoidal division. 



Blood Supply. — Internal pudic. 



Coccygeus. — Description. — This muscle is situated parallel to the Levator 

 ani but behind it. Its upper border is separated from the lower border of the 

 Pyriformis muscle by the internal pudic vessels and nerves. 



PLATE CCLXI. 



ANTERIOR 

 BORDER. 



GROOVE FOR 

 SEPTAL CARTILAGE 



ALA. 



P031. POST. SUP. 



BORDER. ) Wk I VIEW. 



Ha 



GROOVE FOR NASO- PALATINE 

 NERVE 



The Vomer. 



ALA. 



Origin. — From the apex of the spine of the ischium and from the lesser 

 sacro-sciatic ligament. 



Insertion. — Into the margin of the coccyx and side of lower piece of 

 sacrum. 



Action. — Raises and supports coccyx. 



Nerve Supply. — Branch from the fourth and fifth sacral nerves. 



Blood Supply. — Internal pudic. 



LESSON CLX. 



Muscles of the Perineum in the Mali:. (Plate CCLXXI.) 



Transversus perinsei. — Description. This muscle, which passes across 



the back part of the perineal space, is a narrow muscular slip. 



Origin. — From the inner and forepart of the tuberosity of the ischium by 

 a small tendon. 



Insertion. — Into the central tendon of the perineum. 



Nerve Supply. — Perineal branch of the internal pudic. 



Blood Supply. — Internal pudic. 



