T02 LIGAMENTS OF THE SHOULDER. 



Development. The phalanges are developed from two 

 centres one for the base and one for the shaft. Ossifica- 

 tion begins about the same time as in the metacarpal bones, 

 and is observed first in the third phalanx, then in the first, 

 and last of all in the second phalanx. During the third 

 and fourth years the epiphyses of the first row are seen ; 

 during the fourth and fifth those of the second row ; and 

 during the sixth and seventh year those of the last row. 

 All the phalanges are completed by the twentieth year. 



SECTION V. 

 LIGAMENTS OF THE SUPERIOR EXTREMITY. 



The ligaments to be considered are those of the shoulder, 

 arm, forearm, and hand. 



LIGAMENTS OF THE SHOULDER. 



The bones of the shoulder being composed of the clavicle 

 and scapula, we have clavicular and scapular ligaments ; 

 and the clavicle being connected with the sternum, ribs, 

 and scapulae, we have hence a division of the ligaments 

 into sterno-clavicular, costo-clavicular, and scapulo-cla- 

 vicular. 



Sterno-clavicular articulation, (Fig. 141.) This articula- 

 tion has a capsular ligament, an inter-articular cartilage, 

 an inter-clavicular ligament, and two synovial membranes. 



The capsular ligament is a strong, fibrous, membrane 

 surrounding the joint, and covered by the origin of the 

 sterno-cleido-mastoideus at its anterior portion. This cap- 

 sule has its fibres thickened in front and behind -hence 

 the names of the anterior and posterior sterno-clavicular 

 ligaments. 



The anterior, called also the radiated ligament, proceeds 

 from the anterior extremity of the clavicle downward 

 and inward to the articular margin of the cavity of the 

 sternum. The posterior is not so distinct, but pursues a 

 course behind the joint similar to the anterior. 



The inter-articular cartilage is seen on opening the joint. 

 It is circular in shape, and completely separates the ster- 



