278 SKELETON. 



which is manifested not by the bones separating, but by their 

 sliding upwards and downwards with great readiness. The sa- 

 cro-iliac junction also becomes relaxed. It was upon the ob- 

 servation of these facts, that the clebrated, but now exploded, 

 Sigaultian operation was founded. 



The Anterior Pubic ligament is not very distinct. It lies in 

 front of the last articulation, and consists in a few oblique and 

 transverse fibres gomg from the one bone to the other. 



The Sub or Inter-Pubic Ligament (Lig. Pubis Inferius) oc- 

 cupies the summit of the arch of the pelvis. It is of a trian- 

 gular form, about half an inch in breadth, and passes from the 

 margin of the crus of the pubes of the one side, to a corre- 

 sponding line on the other. It is remarkably strong, and is ra- 

 ther more so below than above. It seems rather an extension 

 of the ligament of the symphysis pubis, than a distinct struc- 

 ture. 



CHAPTER VII. 



ARTICULATIONS OF THE THORAX. 



Posterior Articulations of the Ribs. 



As mentioned, in the account of the bones, the articulations 

 here are double; being formed at one point between the heads 

 of the ribs and the bodies of the vertebrae with the inter-verte- 

 bral matter; and at the other, between the tubercles of the ribs 

 and the transverse processes. In either case the respective 

 surfaces are covered by articular cartilage, and have a syrio- 

 vial membrane. The first joint is the Costo- vertebral, and the 

 second the Costo-transverse. 



1. The Costo- vertebral articulation presents an anterior liga- 

 ment, an inter-articular ligament, and two synovial membranes. 

 The Anterior or Radiating Ligament, (Lig. Capituli Costa- 



