DISSECTION OF THE UPPER EXTREMITY 



85 



midway between its origin and its insertion and the caput longum 

 of the M. biceps four centimetres below its origin. Reflect these 

 muscles. Carefully dissect from the capsule of the joint the Mm. 

 supraspinatus, infraspinatus, teres minor, and subscapularis. 



FIG. 26. 



Cavity of the articulatio 

 acromioclavicularis 



Clavicula --' 



M. supraspinatus 



Labrum glenoidale 



Bursa subdel- 

 toidea 



M. deltoideus 





M. triceps 



Synovia! membrane and 

 joint-capsule 



M. teres major 



Articulatio humeri, frontal section passing through the tuberositas minor, the arm adducted. 

 Poirier et Charpy, Traite d'Anat. hum., Paris, 1899, 2 ed., t. i. p. 624, Fig. 636.) 



(From 



Clean the surfaces of the ligaments carefully, 

 lowing : 



Study the fol- 



(a) Articular capsule (capsula articularis) . 



Note its cone shape, the summit attached to the labrum glenoi- 

 dale, its base to the anatomical neck of the humerus. The attach- 

 ment goes beyond the anatomical neck behind and below. Observe 

 the variations in the thickness of the capsule in different parts. 



(b) Coracohumeral ligament (ligamentum coracohumerale) (0. T. acces- 



sory ligament). 



How is it attached medialward and lateralward ? Note that it 

 corresponds to the interval between the tendons of the M. supra- 

 spinatus and M. subscapularis, and so strengthens the capsule in a 

 region otherwise feebly protected. 



(c) Glenohumeral ligaments. (Cf. Fig. 27.) 



Dissect off the posterior part of the capsula articularis, 

 pull the bones well apart, look into the joint from behind, 





