142 THORAX 



and no interarticular ligament. There is, however, consider- 

 able variety in these articulations, and a synovial stratum is 

 very frequently wanting altogether in the joint between the 

 seventh costal cartilage and the sternum. 



With the exception of the first, which is a synchondrosis, 

 the sterno-chondral joints belong to the diarthrodial variety. 

 They are provided with anterior and posterior ligaments, and 

 also, in those cases where the joint presents a double synovial 

 cavity, with an interarticular ligament. 



Ligamenta Sternocostalia Radiata. The radiate sterno- 

 costal ligaments are strong fibrous strands of the articular 

 capsules of the sterno-costal joints. They radiate from the 

 anterior and posterior surfaces of the sternal ends of the 

 costal cartilages, from the second to the sixth, to the adjacent 

 parts of the anterior and posterior surfaces of the sternum. 



Ligamenta Sternocostalia Inter articular ia. The interarticular 

 sterno-costal ligaments are feeble bands which attach the tips 

 of the rib cartilages to the sides of the sternum. They divide 

 the cavities of the joints in which they exist into upper and 

 lower compartments each of which is lined with a synovial 

 stratum. 



Articulationes Interchondrales. The interchondral joints 

 are formed between the adjacent margins of the ribs, from 

 the sixth to the tenth. The joint cavities are surrounded 

 by ordinary articular capsules, each of which is lined internally 

 with a synovial stratum ; they are, therefore, diarthrodial 

 joints. 



Articulationes Costovertebrales. The costo-vertebral joints 

 are separable into two groups articulationes capitulorum and 

 articulationes costo-transversarise. 



The capitular articulations are the joints between the heads 

 of the ribs and the bodies of the vertebrae and the interverte- 

 bral fibro-cartilages ; they are diarthrodial joints. With the 

 exceptions of the first rib and the last three ribs, the head of 

 every rib articulates with the bodies of two adjacent vertebrae 

 and the intervening intervertebral fibre-cartilage, and it is 

 connected with them by an articular capsule and an inter- 

 articular ligament. The interarticular ligament connects the 

 intervertebral fibro-cartilage with the ridge which separates 

 the two facets on the head of the rib. It is united, anteriorly 

 and posteriorly, with the capsule, and separates the joint cavity 

 into an upper and a lower compartment. The anterior part 



