OF THE RIBS WITH THE VERTEBRA. 



331 



INTERARTICULAR LIQAME 



Loirer synovia! carity. 



FIG. 235. Costo-vertebral and costo-transveree articulations. Ante- 

 rior view. 



exist : but the fibres of the ligament in each case radiate and are connected with 

 the vertebra above, as \vell as that with which the ribs articulate. 



The Capsular Ligament is a thin and loose ligamentous bag. which surrounds 

 the joint between the head of the rib and the articular cavity formed by the 

 inrervertebral disk and the 

 adjacent vertebra. It is 

 very thin, firmly connected 

 with the anterior ligament, 

 and most distinct at the 

 upper and lower parts of 

 the articulation. Behind, 

 some of its fibres pass 

 through the intervertebral 

 frarnen to the back of the 

 intervertebral disk. This 

 is the analogue of the Hga- 

 mentum conjugate of some 

 mammals, which unites the 

 heads of opposite ribs a 

 the back of the interverte- 

 bral disk. 



The Interarticular Liga- 

 ment is situated in the 

 interior of the joint. It 

 consists of a short band of 

 fibres, flattened from above 

 downward, attached by one 

 extremity to the sharp 

 crest on the head of the 

 rib, and by the other to the intervertebral disk. It divides the joint into two cavities, 

 which have no communication with each other. In the first, tenth, eleventh, and 

 twelfth ribs the interarticular ligament does not exist ; consequently, there is but 

 one synovial membrane. , 



The Synovial Membrane. There are two synovial membranes in each of the 

 articulations in which there is an interarticular ligament, one on each side of this 

 structure. 



2. ARTICULATIONS OF THE XECKS AND TUBERCLES OF THE RIBS WITH 



THE TRANSVERSE PROCESSES (Fig. 236). 



The articular portion of the tubercle of the rib and adjacent transverse process 

 form an arthrodial joint. 



In the eleventh and twelfth ribs this articulation is wanting. 

 The ligaments connecting these parts are the 



Superior Costo-transverse. 



Middle Costo-transverse (Interosseous). 



Posterior Costo-transverse. 



Capsular. 



The Superior Costo-transverse Ligament has two sets of fibres : the one (anterior 

 costo-transi'erse liyam>-nt) is attached to the crest on the upper border of the neck 

 of each rib. and passes obliquely upward and outward to the lower border of the 

 transverse process immediately above ; the other (posterior costo-transverse liga- 

 ment] is attached to the neck of the rib, and passes upward and inward to the base 

 of the transverse process and border of the lower articular process of the vertebra 

 above. This ligament is in relation, in front, with the intercostal vessels and 

 nerves; behind, with the Longissimus dorsi. Its internal border completes an 

 aperture formed between it and the articular processes, through which pass the 



