STERNOCLAV1CULAR ARTICULATION 



295 



part of the joint, but it occasionally reaches to the front, and may extend the 

 entire length of the cartilage. This cavity may sometimes be demonstrated by 

 making a vertical section of the symphysis pubis near its posterior surface 

 (Fig. 242). 



The obturator ligament is more properly regarded as analogous to the mus- 

 cular fasciae, with which it will be described. 



ARTICULATIONS OF THE UPPER EXTREMITY. 



The articulations of the upper extremity may be arranged in the following 

 groups : 



I. Sternoclavicular Articulation. 



II. Acromioclavicular Articulation. 

 III. Ligaments of the Scapula. 

 IV. Shoulder-joint. 



V. Elbow-joint. 

 VI. Radioulnar Articulations. 



VII. Wrist-joint. 



VIII. Articulations of the Carpal Bones. 

 IX. Carpometacarpal Articulations. 

 X. Metacarpophalangeal Articula- 

 tions. 

 XI. Articulations of the Phalanges. 



I. Sternoclavicular Articulation (Articulatio Sternoclavicularis) (Fig. 243). 



The Sternoclavicular is an arthrodial joint. The parts entering into its forma- 

 tion are the sternal end of the clavicle, the upper and lateral part of the first piece 

 of the sternum, and the cartilage of the first rib. The articular surface of the 



FIG. 243. Sternoclavicular articulation. Anterior view. 



sternum is covered with hyaline cartilage. The articular surface of the clavicle 

 is much larger than that of the sternum, and invested with a layer of hyaline 

 cartilage 1 which is considerably thicker than that on the latter bone. The liga- 

 ments of this joint are the 



Capsular. 



Anterior Sternoclavicular. 



Posterior Sternoclavicular. 



Interclavicular. 

 Costoclavicular. 

 Articular Disk. 



1 According to Bruch, the sternal end of the clavicle is covered by a tissue which is rather fibrous than 

 cartilaginous in structure. 



