OF THE PELVIS 



201 



interosseous, or symphysial, cartilage. The bones which enter into the joint are 

 die sacrum and ilium, and they are bound together by the following ligaments: — 



Anterior saero-iliae. 

 Posterior sucro-iliac. 



Interosseous. 



Superior sacro-iHac. 

 Inferior sacrcj-iliac. 



The anterior sacro-iliac ligament (figs. 200 and 207) consists of well-marked 

 glistening fibres wliich pass above into the sujierior, and below into the inferior, 

 ligaments. It extends from the first three bones of the sacrum to the ilium between 

 the brim of the true pelvis and the great sacro-sciatic notch, blending with the 

 periosteum of the sacrum and ilium as it passes away from the united edges of the 

 bones. 



The superior sacro-iliac ligament (figs. 206 and 207) extends across the ui)per 

 margins of the joint, from the base of the sacrum to the iliac fossa, being well 



Fig. 207. — Vertical A xtero- posterior Section of the Pelvis. 



Superior saoro-iliao 

 ligament 



Anterior sacro-iliac 



ligament 



Inferior Baero-iliao 



ligament 



Small sacro-sciatic 

 ligament 



Great sacro-sciatic 

 ligament 



marked along the brim of the pelvis, where it is thickened l>y some closely-packed 

 fibres. Behind, it is far stronger, especially beneath the transverse process of the 

 fifth lumbar vertebra. This ligament is connected with the strong sacro-lumbar 

 ligament, which spreads outwards and forwards over the joint to reach the iliac 

 fossa and ilio-pectineal line. 



The posterior sacro-iliac ligament is of very great strength, extending l)etween 

 the back of the sacrum and the posti'rior two inches of the iliac crest, including the 

 posterior superior spine. Strengthening the upper and liack part of this fibrous 

 expansion are some strong Inmdles of ligamentous fibres, which extend more or less 

 transversely from the inner surface of the iliac crest: (i) to the articular process of 

 the first sacral vertebra; (ii) to the l)one between the articular process and the first 

 sacral foramen; and (iii) to the articular tubercle of the second sacral Tertcl)ra, 

 forming a ridge over the second sacral foramen under Avhich the nerve passes; an 

 ol)lique band often connects this last fasciculus with the articular process of the 

 first sacral vertebra. Below this, the fibres pass downwards and inwardis from the 



