THE ABDOMEN, INTERIOR. 553 



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obturator fascia, to supply the structures of the perineum, 

 see page 4 1 3. (Ji) The great sciatic nerve. This is the 

 termination of the sacral plexus. It is the largest nerve in 

 the body. From its origin it passes outward through the 

 great sacrosciatic foramen below the pyriformis muscle into 

 the gluteal region ; for further course, see page 610. 



The sacral gang-Hated cord is the continuation of the 

 lumbar cord from behind the iliac vessels to the central 

 ganglion (impar) over the front of the coccyx ; there are 

 four small ganglia usually in the course of the cord, but 

 may be fewer. 



