SHOULDER-JOINT 



119 



ARTICULATIO HUMERI (SHOULDER-JOINT). 



After the structures situated in the arm have been examined 

 the dissection of the shoulder-joint should be commenced, in 

 order that the ligaments may be examined before they have 

 become too dry. 



The shoulder-joint belongs to the enarthrodial or ball and 



Supraspinatus 



Scapula 



Subscapularis 



Serratus anterior 



Capsule of joint 



Humerus 

 Deltoid 



Fold of capsule 

 of joint 



Posterior circumflex artery 

 of humerus and axillary 

 (O.T. circumflex) nerve 



Teres major 



Radial (O.T. musculo-spiral) 

 nerve 



Latissimus dorsi 



FIG. 50. Frontal or vertical transverse section through the Left 

 Shoulder-joint. (Viewed from behind. ) 



socket sub-group of the diarthrodial or completely movable 

 joints. The socket is formed by the glenoid cavity of the 

 scapula and the ball is the spheroidal head of the humerus. 



In no joint in the body are the movements so free and so 

 varied in their character as in the shoulder-joint. This is 

 rendered necessary by the many functions which are performed 

 by the upper limb. Freedom of movement is provided for in 

 two ways (i) by the large size of the head of the humerus, 

 in comparison with the small dimensions and shallow character 



