616 ABDOMEN 



Ligamentum Sacroiliacum Interrosseum. The interosseous 

 sacro-iliac ligament is exceedingly strong. It consists of fibrous 

 bands, which connect the rough surface on the posterior part 

 of the lateral aspect of the sacrum with a corresponding rough 

 surface on the ilium, behind the auricular surface. Upon 

 the interosseus sacro-iliac ligaments the strength of the articu- 

 lation chiefly depends. As the sacrum narrows towards its 

 dorsal surface it cannot be regarded as forming a typical key- 

 stone of an arch. It may be regarded as being, in a great 

 measure, suspended from the iliac bones by ligaments. 



Short posterior sacro-iliac 

 nt 



Sacro-iliac joint 



Small sciatic 

 foramen 



Acetabulum 

 Lig. sacro-tuberosut 



-Inter-pubic fibro-cartilage 

 FIG. 243. Coronal section through the Pelvis. 



Ligamentum Sacroiliacum Posterius Longum. The long 

 posterior sacro-iliac ligament is fixed above to the posterior 

 superior spine of the ilium ; whilst, inferiorly, it is inserted 

 into the third tubercle on the posterior surface of the 

 lateral mass of the sacrum. It lies posterior to the 

 interosseous ligament. 



Ligamentum Sacroiliacum Posterius Breve. The short 

 posterior sacro-iliac ligament also lies behind the interosseous 

 ligament, and is a short band of fibres which extends from 

 the posterior inferior spine of the ilium to the back of the 

 sacrum. 



Ligamentum Sacrotuberosum (O.T. Great Sacro-sciatic Liga- 



