ARTICULATIONS 7 



lumbar vertebra; below, to the outer border of the front of 

 the lateral mass of the sacrum. 



The ilio-lumbar ligament passes from the tip of transverse 

 process of 5th lumbar vertebra, to the crest of L.um in front 

 of sacro-iliac articulation. 



XII. ARTICULATIONS OF THE PELVIS. 



(a) Sacro-iliac Joint. 



The sacro-iliac articulation is an amphiarthrosis, formed 

 between the lateral surfaces of the sacrum and ilium. The 

 auricular or anterior parts of the articular surfaces are covered 

 with cartilage, and connected by the two following ligaments : 



The anterior sacro-iliac ligament : small bands passing 

 obliquely from sacrum to ilium on the anterior surface. 



The posterior sacro-iliac ligament consists of strong inter- 

 osseous bands passing chiefly downwards and inwards from 

 the rough part of the ilium behind the cartilage, to the 

 posterior part of the sacrum. There are two superior, passing 

 from the ist and 2nd transverse sacral tubercles, and one 

 sometimes called the oblique sacro-iliac ligament, which reaches 

 from the posterior superior iliac spine to the 3rd transverse 

 sacral tubercle. 



(b) Ligaments between the Sacrum and Ischium. 



The great (or posterior] sacro-sciatic ligament, attached by 

 its base to the posterior inferior iliac spine, to the 4th and 5th 

 transverse sacral tubercles, and to the lower part of the edge 

 of the sacrum and coccyx ; passes downwards, outwards, and 

 forwards, to be attached to the inner edge of the ischial 

 tuberosity and to the inner margin of the ramus, forming the 

 falciform ligament. 



The small (or anterior] sacrp-sciatic ligament, attached by 

 its apex to the spine of the ischium, and by its base to the 

 lateral margin of the coccyx and sacrum. 



Foramina. Between the great sacro-sciatic ligament and 

 the innominate bone is a space divided into two by the small 

 sacro-sciatic ligament ; the part above this ligament being the 

 great sacro-sciatic foramen, and the part between the two liga- 

 ments the small sacro-sciatic foramen. The large foramen 

 transmits pyriformis, together with superior gluteal, sciatic 

 and internal pudic vessels, the superior gluteal, great and 

 small sciatic, pudic and inferior gluteal nerves, and nerves to 

 the obturator internus, quadratus, and gemelli. The small 

 foramen transmits the obturator internus, whilst its nerve, 

 together with the internal pudic vessels and pudic nerve, re- 

 enters the pelvis by it. 



