128 LIGAMENTS OF THE RIBS. 



wards on the eminentia articularis, carrying with it the condyle. If 

 this movement be carried too far, the superior synovial membrane is 

 ruptured, and dislocation of the fibro-cartilage with its condyle into 

 the zygomatic fossa occurs. In elevation the fibrous cartilage and con- 

 dyle are returned to their original position. The forward and back- 

 ward movement is a gliding of the fibro-cartilage upon the glenoid 

 articular surface, in the antero-posterior direction ; and the movement 

 from side to side, in the lateral direction. 



6. Articulation of the Ribs with, the, Vertebra. The ligaments of 

 these articulations are so strong as to render dislocation impossible, the 

 neck of the rib would break before displacement could occur ; they are 

 divisible into two groups: 1. Those connecting the head of the rib 

 with the bodies of the vertebras ; and, 2. Those connecting the neck 

 and tubercle of the rib with the transverse processes. They are 



1st Group. 



Anterior costo-vertebral or stellate, 

 Capsular, 

 Interarticular ligament, 



Two synovial membranes. 



2nd Group. 



Anterior costo-transverse, 

 Middle costo-transverse, 

 Posterior costo-transverse. 



The anterior costo-vertebral or stellate ligament (fig. 50) consists of 

 three short bands of ligamentous fibres that radiate from the anterior 

 part of the head of the rib. The superior band passes upwards, and 

 is attached to the vertebra above ; the middle fasciculus is attached 

 to the intervertebral substance ; and the inferior, to the vertebra 

 below. 



In the first, eleventh, and twelfth ribs, the three fasciculi are attached 

 to the body of the corresponding vertebra. 



The capsular ligament is a thin layer of ligamentous fibres surround- 

 ing the joint in the interval left by the anterior ligament ; it is thick- 

 est above and below the articulation, and protects the synovial mem- 

 branes. 



The interarticular ligament is a thin band which passes between the 

 sharp crest on the head of the rib and the intervertebral substance. 

 It divides the joint into two cavities, which are each furnished with a 

 separate synovial membrane. The first, eleventh, and twelfth ribs have 

 no interarticular ligament, and consequently but one synovial mem- 

 brane. 



The anterior costo-transverse ligament is a broad band composed of 

 several fasciculi, which ascend from the crest-like ridge on the neck of 

 the rib, to the transverse process immediately above. This ligament 



