PELVIS MINOR 473 



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

 stone of an arch. On the contrary, it is suspended from the 

 iliac bones by the posterior sacro-iliac ligaments. 



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

 ment}. The sacro-tuberous ligament has a wide attachment 

 to the posterior superior and posterior inferior iliac spines and 

 to the side of the sacrum and coccyx. As it passes down- 

 wards and forwards it narrows and thickens, but before 

 reaching its termination it again expands. It is inserted into 

 the medial border of the tuberosity of the ischium. Thence 



Interosseous sacro-iliac 

 ligament 



.Cavity of 

 sacro-iliac joint 



Lig. sacro- 

 spinosum 



Lesser sciatic 

 foramen 



Acetabulum 

 Lig. sacro-tuberosum 



-Interpubic fibro-cartilage 

 FIG. 219. Frontal section through the Pelvis. 



it sends a sharp falciform process forwards for a short distance 

 upon the inferior ramus of the ischium, and gives attachment 

 to the parietal pelvic fascia. It should be noticed that at its 

 ischial attachment some of the fibres of the ligament pass 

 directly into the tendon of the biceps femoris muscle. 



Ligamentum Sacrospinosum (O.T. Small Sacro-sciatic Liga- 

 ment). The sacro-spinous ligament is triangular in form. By 

 its base it is fixed to the side of the sacrum and coccyx, in 

 front of the sacro-tuberous ligament, the fibres of both 

 mingling together ; by its apex it is attached to the spine 

 of the ischium. The pelvic surface of this ligament presents 

 an extremely intimate connection with the coccygeus muscle ; 



