PELVIS 



583 



sacrum and coccyx. It is, therefore, curved with the con- 

 cavity forwards. Beyond the coccyx the lower inch and a 

 half of the rectum is supported by pelvic floor, formed by 



4th sacral 

 vertebra (cut) 

 Piriformis 

 (cut) 



Superior 

 haemor- 

 rhoidal artery 



Lig. sacro- 

 tuberosum 



Ischio-rectal 

 fossa 



Anal canal 



Anus 



External 

 ncter 



FIG. 230. Dissection of the Rectum from behind. The sacrum below the 

 4th sacral vertebra and also the coccyx have been removed. Portions 

 of the levatores ani, coccygei, and external sphincter have also been 

 taken away. (Birmingham.) 



the levatores ani muscles, and by the ano-coccygeal body. The 

 ano-coccygeal body consists of a dense mass of fibrous tissue 

 which fills the interval between the coccyx and the anus. 

 It receives the insertion of some of the fibres of the levatores 



