PELVIS 613 



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 ad- 

 hering portions of muscle, must now be removed from the innominate 

 bone and from the front and back of the sacrum. When this is done the 

 pelvis should be soaked for some time in warm water. By this proceeding 

 the dissection of the ligaments will be rendered 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. 



Capsulce Articulares (Capsular ligaments] surround the 

 articulations formed by the apposition of the articular pro- 

 cesses. 



Ligamentum Longiiudinale Anterius (O.T. Anterior Common 

 Ligament}. The anterior longitudinal ligament of the vertebral 

 column is continued downwards, over the anterior aspect of 

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

 of the first segment of the sacrum. In a"^milar manner the 

 ligamentum longitudinale posterius is prolonged downwards, 

 within the spinal 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. 



Ligamenta Flava (O.T. Ligamenta Subflava) are also present. 

 These are two short bands of yellow elastic tissue placed one 

 on each side of the medial plane. Superiorly they are attached 

 to the anterior aspect of the lower borders of the laminae of 

 the last lumbar vertebra ; whilst inferiorly they are fixed to 

 the posterior aspect of the upper margins of the laminae of 

 the first sacral segment. 



Ligamentum Interspinale. An interspinous ligament 

 connects the lower border of the spinous process of the 

 last lumbar vertebra with the upper border of the spinous 

 process of the first sacral vertebra. A ligamentum supraspinale 

 passes between the extremities of the same spinous processes. 



So far, then, the ligaments of the lumbo-sacral articulations 

 are identical with those which, above the level of the sacrum, 

 bind the several segments of the spinal column together. 

 Two additional ligaments, viz. the lumbo-sacral and the ilio- 

 lumbar, must now be examined. 

 I 39 & 



