Joints of the Lower Extremity. 193 



The pelvic bones are connected by means of two joints: - the paired arti- 

 culatio sacroiliaca and the unpaired symphysis ossium pubis, 



In the articulatio sacroiliaca (see also Figs. 244 and 245) the facies 

 auricularis ossis sacri and the facies auricularis ossis ilium of each side are in contact. 

 A short, tight capsula articularis connects the margins of the cartilaginous surfaces; 

 it is strengthened on the anterior surface by the ligamenta sacroiliaca anteriora, 

 which, considered as a whole, run as broad thin fibre plates from the lateral portion 

 of the basis and facies pelvina of the sacrum transversely to the medial surface of the 

 ilium and are there attached in the periphery of the linea arcuata, eventually also in 

 the sulcus' paraglenoidalis. 



The lig amentum iliolumbale (0. T. iliolumbar ligament) (see also Fig. 244), 

 must also be regarded as a strengthening ligament (in the wider sense) for this joint. 

 This forms a powerful flat fibre band which has its origin from the processus transversus 

 of the fifth (partially also, as in Fig. 243, of the fourth) lumbar vertebra; one part 

 of the fibres extends from there to the posterior portion of the crista iliaca, another 

 larger part broadens out on the inner surface of the ala ossis ilium and on the upper 

 surface of the pars lateralis ossis sacri. 



Spaltehol/, Atlas. 13 



