176 



Joints of the Upper Extremity. 



Ligamentum costoclaviculare 



Ligamentum sternoclaviculare 



Ligamentum interclaviculare 

 Discus articularis 



i 

 Costa I 



Manubrium sterni 



227. Clavicle, sternum and first rib, with liga- 

 ments, from in front. 



(On the left half the most anterior layer has heen removed; the parts forming the joints are 



somewhat separated from another.) 



The articulatio sternoclavicularis (sternoclavicular joint) arises from the 

 fact that the extremitas sternalis claviculae with its facies articular sternalis, covered 

 with cartilage, lies in the incisura clavicularis sterni which is also covered with carti- 

 lage, the two being separated only by the discus articularis (0. T. interarticular fibro- 



. 



cartilage); the latter is thickened above, medianward and behind, and separates two special 

 joint cavities with capsulae articular es from one another. The discus articularis and 

 the cartilaginous coverings consist of fibrocartilage. On the anterior surfaces of the 

 joint the broad ligamentum sternoclavicular e extends from the clavicle clown to the 

 sternum. In addition, the rounded, unpaired ligamentum interclaviculare, concave 

 above, stretches out between the medial extremities of the two clavicles over the incisura 

 jugularis sterni. The ligamentum costoclaviculare (0. T. rhomboid ligament), a power- 

 ful ligament, consisting of several layers, goes from the tuberositas costalis claviculae to 

 the upper margin of the first costal cartilage. 



