IS Y Mm Y SIS rUBlJS. 337 



Lig. Iliolumbale. The ilio-lumbar ligament (Fig. 314), which is merely the 

 thickened anterior lamina of the lumbo-dorsal fascia, extends from the tip of the 

 transverse process of the 'last lumbar vertebra, almost horizontally laterally, to 

 the inner lip of the iliac crest at a point a short distance behind its highest level. 

 A proportion of these fibres is attached to the medial rough surface of the ilium 

 between the iliac crest and the auricular impression. To these the name of the 

 lig. iliolumbale inferius is applied. 



Lig. Sacrotuberosum. The sacro-tuberous ligament (O.T. great sacro-sciatic 

 lig.) (Fig. 314) is somewhat triangular in outline. It occupies the interval between 

 the sacrum and the hip bone, and is attached medially to the posterior inferior 

 spine of the ilium ; to the posterior aspects of the tubercles of the transverse processes 

 and lateral margins of the third, fourth, and fifth segments of the sacrum, as well as 

 to the side of the first segment of the coccyx. It passes downwards and laterally, 

 becoming narrower as it approaches the ischium, near to which, however, it again 

 expands, to be attached to the medial side of the tuber ischiadicum, immediately 

 below the groove for the tendon of the obturator internus muscle, i.e. the lesser 

 sciatic notch. A continuation of the medial border of the ligament the processus 

 falciformis (Fig. 314) runs upwards and forwards on the medial aspect of the 

 ramus of the ischium. 



The ligamentum sacrotuberosum is believed by many to represent the original 

 or proximal end of the long or ischial head of the biceps femoris muscle. 



Ligamentum Sacrospinosum. The sacro-spinous ligament (O.T. small sacro- 

 sciatic lig.) (Figs. 314 and 313) is situated in front, and in a measure under cover 

 of the sacro-tuberous ligament. Triangular in form, it is attached by its base to 

 the last two segments of the sacrum and the first segment of the coccyx, and by its 

 [ pointed apex to the tip and superior aspect of the spina ischiadica. This ligament 

 i is intimately associated with the coccygeus muscle, and by some it is regarded as 

 ; being derived from it by fibrous transformation of the muscle fasciculi. 



By the sacro-tuberous and sacro-spinous ligaments the two sciatic notches of 

 the hip bone .are converted into foramina. Thus the sacro-spinous ligament (lig. 

 sacrospinosum) completes the boundaries of the greater sciatic foramen (foramen 

 ischiadicum majus) ; while the sacro - tuberous ligament (lig. sacrotuberosum), 

 l assisted by the sacro-spinous ligament (lig. sacrospinosum), closes the lesser sciatic 

 foramen (foramen ischiadicum minus). 



SYMPHYSIS OSSIUM PUBIS. 



The anterior wall of the osseous pelvis is completed by the articulation of the 

 bodies of the two pubic bones, which constitutes the symphysis pubis. This joint 

 \., sonforms in its construction to the general plan of an amphiarthrosis. Thus it is 

 median in position ; each pubic bone is covered by a layer of hyaline cartilage, 

 which closely adapts itself to the rough tuberculated surface of the pubic bone ; 

 while between these two hyaline plates there is an interposed fibro- cartilage 

 3alled the lamina fibrocartilaginea interpubica, in the interior of which there is 

 isually a vertical antero-posterior cleft. This cavity, which is placed nearer the 

 posterior than the anterior aspect of the joint, does not appear until between the 

 seventh and tenth years, and as it is not lined by a synovial stratum, it is supposed 

 ;o result from the breaking down of the interpubic lamina. 



Lig. Pubicum Anterius. The anterior pubic ligament (Fig. 313) is a structure 

 >f considerable thickness and strength. Its superficial fibres, which are derived 

 ^ery largely from the tendons and aponeuroses of adjoining muscles, are oblique, 

 md form an interlaced decussation. The deeper fibres are short, and extend 

 ransversely from one pubic bone to the other. 



Lig. Pubicum Posterius. The posterior pubic ligament (Fig. 313) is very 

 veak and consists of scattered fibres which extend transversely between contiguous 

 >ubic surfaces posterior to the articulation. 



Lig. Pubicum Superius. The superior pubic ligament also is weak ; it consists 

 'f transverse fibres passing between the two pubic crests. 



22 



