284 



THE ARTICULATIONS, OR JOINTS 



2. COSTOTRANSVERSE ARTICULATIONS (ARTICULATIONES COSTOTRANSVERSARIAE) 



(Fig. 234). 



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

 form an arthrodial joint. 



For the eleventh and twelfth ribs this articulation is wanting. 

 The ligaments connecting these parts are the 



Anterior Superior Costotransverse. 

 Middle Costotransverse (Interosseous). 



Posterior Costotransverse. 

 Capsular. 



The anterior superior ligament (ligamentum costotransversarium anterius) 

 (Figs. 234 and 235) consists of two sets of fibres; the one (anterior) is attached 

 below to the sharp crest on the upper border of the neck of each rib, and passes 



INTRA-ARTICULAR 

 LIGAMENT 



SYNOVIAL 

 MEMBRANE 



ANTERIOR COSTOTRANSVERSE 

 LIGAMENT DIVIDED. 



MIDDLE COSTOTRANSVERSE 



Or INTEHOSSEOUS 

 POSTERIOR COSTO- 

 TRANSVERSE LIGAMENT. 



FIG. 234. Costotransverse articulation. Seen from above. 



obliquely upward and outward to the lower border of the transverse process 

 immediately above; the other (posterior) is attached below to the neck of the rib, 

 and passes upward and inward to the base of the transverse process and outer 

 border of the lower articular process of the vertebra above. 



The first rib has no anterior Costotransverse ligament. For the twelfth rib the 

 ligament is absent or is a mere vestige. 



Relations. This ligament is in relation, in front, with the intercostal vessels and nerves; 

 behind, with the Longissimus dorsi muscle. Its internal border is thickened and free, and bounds 

 an aperture through which pass the posterior branches of the intercostal vessels and nerves. Its 

 external border is continuous with a thin aponeurosis which covers the External intercostal 

 muscle. 



The middle Costotransverse or interosseous ligament (ligamentum collicostae) 

 (Fig. 234) consists of short but strong fibres which pass between the rough surface 

 on the posterior part of the neck of each rib and the anterior surface of the ad- 

 jacent transverse process. In order to fully expose this ligament, a horizontal 



