PELVIS 



605 



and its posterior margin is separated from the lower border 

 of the piriformis by the inferior glutaeal and pudendal vessels 

 and the sciatic and pudendal nerves as they pass out of the 

 pelvis. 



The Pelvic Nerve Plexuses. There are two pelvic spinal 

 nerve plexuses, viz. the sacro-pudendal and the coccygeal. The 



LIV 



5.1 _ 



To piriformis ZT 



To piriformis . 



Visceral 



SJ 



Visceral ... 



f . Lumbo-sacral cord 



Superior glutaeal nerve 



Inferior glutaeal nerve 



Nerve to quadratus femoris 

 Nerve to obturator interm 



Sciatic nerve 



Common 

 peronaeal nerve 



Sciatic nerve 



Tibial nerve 



Post. cut. N. of thigh (O.T. small sciatic) 

 Perineal N. and dorsal N. of penis \ Pudendal 

 Inferior ha^morrhoidal nerve / nerve 



% -, Perforating cutaneous nerve 



v v ' Nerves to levator ani 

 Coccygeal branches 



FIG. 241. Diagram of Sacral Plexus. 



former is situated on the posterior wall of the pelvis in front 

 of the piriformis muscle, and the latter lies on the coccygeus 

 muscle close to the side of the coccyx. 



The Sacro-Pudendal Plexus (O.T. Sacral Plexus). The 

 anterior primary divisions of six spinal nerves take part in 

 the formation of this plexus, viz., part of the fourth lumbar 

 nerve, the fifth lumbar, the first, second, and third sacral 

 nerves, and part of the fourth sacral nerve. The first and 



