PELVIS MINOR 469 



of the second, third, and fourth sacral segments, between and 

 lateral to the foramina and, to a slight extent, medial to the 

 foramina ; it takes origin also from the upper border of the 

 greater sciatic notch and from the sacro-tuberous ligament. 

 The muscle leaves the pelvis through the upper part of the 

 greater sciatic foramen, and is inserted, by a rounded tendon, 

 into the middle of the upper border of the greater trochanter 

 of the femur. It is supplied by branches from the first and 

 second sacral nerves. Its actions are the same as those of 

 the obturator internus. 



LlGAMENTA ClNGULI EXTREMITATIS INFERIORIS (LIGAMENTS 

 OF THE PELVIC ARTICULATIONS). 



The pelvis is attached to the last lumbar vertebra at the 

 lumbo- sacral articulation, and its several parts are held 

 together by the following articulations: (i) Sacro-coccygeal ; 

 (2) Coccygeal; (3) Sacro-iliac ; (4) Pubic. 



Dissection. The nerves and blood-vessels of the pelvis, and 

 all adhering portions of muscle, must now be removed from 

 the hip bone and from the front and back of the sacrum. When 

 that has been done the pelvis should be soaked for some time 

 in warm water, a proceeding which will render the dissection of 

 the ligaments much easier. 



Lumbo-sacral Articulations. The last lumbar vertebra 

 is joined to the sacrum by one synchondrosis, which connects 

 the body of the vertebra to the base of the sacrum, and by 

 two diarthrodial joints, between the two pairs of articular 

 processes. 



Articular capsules, consisting of a fibrous stratum lined 

 with a synovial stratum, surround the articulations formed by 

 the apposition of the articular processes. 



Ligamenta Longitudinalia (O.T. Anterior and Posterior 

 Common Ligaments}. The anterior longitudinal ligament of 

 the vertebral column is continued downwards, over the 

 anterior aspect of the body of the last lumbar vertebra, to 

 the anterior aspect of the first segment of the sacrum. In 

 a similar manner the posterior longitudinal ligament is pro- 

 longed downwards, within the vertebral canal, over the 

 posterior aspect of the body of the last lumbar vertebra, to 

 the upper part of that portion of the sacrum which forms 

 the anterior wall of the sacral canal. 



