THE ABDOMEN 



90^ 



Anterior Pabic ligament 



of the superincumbent weight there is a tendency on the part of 

 the sacrum to rotate round an axis passing transversely through 

 the sacro-iliac joints. This tendency, however, is checked by the 

 great and small sacro-sciatic hgaments. The iho-hmibar ligaments 

 prevent displacement of the fifth lumbar vertebra over the base 

 of the sacnun. 



Symphysis Pubis.— This belongs to the class amphiarthrosis. 

 The articular surfaces are the symphysial aspects of the pubic 

 bones. The ligaments are anterior, posterior, superior, inferior, 

 and interpubic disc. The anterior pubic ligament is strong, and 

 is composed of supeificial and deep fibres. The superficial fibres 

 are arranged in an 



obliquely decussating Suprapubic Ligament 



manner, and are. 

 chiefly constructed by ; 

 the aponeurotic fibres 

 of the external oblique 

 and inner heads of 

 the recti abdominis 

 mu cles. The deep fibres 

 are disposed trans- 

 versely. The posterior 

 and superior pubic liga- 

 ments are weak, and 

 consist of scattered 

 fibres. The inferior or 

 subpubic ligament is a 



strong, thick band of Subpubic ligament 



fibres, which lies at the Fig. 378. — The Ligaments of the Symphysis 

 antero-superior part of Pubis (Anterior Aspect). 



the subpubic arch, 



where it fills up and rounds off the subpubic angle. It is attached 

 superiorly to the lower part of the interpubic disc, and laterally 

 to the adjacent parts of the inner lips of the descending pilbic 

 rami. It is about J inch in depth, and is slightly arched, from 

 which latter circumstance it is Imown as the ligamentiitn arcuatitm. 

 The interpubic disc lies between the plates of cartilage which 

 cover the bony articular surfaces. It is composed of fibro- cartilage, 

 is thicker in front than behind, and usually contains a fissure at 

 its upper and back part, which may extend for one half, or even 

 the whole length, of the disc as an obhque cleft, parallel to the 

 plane of the bony surfaces. This fissure is brought about by 

 absorption of the tissues in that situation, and it does not appear 

 until about the tenth year of hfe. It is larger in the female than 

 in the male. 



The depth of the symphysis pubis is less in the female than in the 

 male. 



Arterial Supply. — Pubic branches of the deep epigastric and 

 obturator, and superior or superficial external pudic arteries. 



