Joints of the Upper Extremity. 



185 



Humerus 



Fossa coronoidea 



Epiphyseal junction 



Trochlea humeri 



Processus coronoideus ulnae 



Fossa olecrani 



Capsula articularis 



Olecranon 



Epiphyseal junction 



.... Ulna 



Radius 



Chorda obliqua 



236. Right elbow joint, articulatio cubiti, 



cut through at right angles to the axis of the trochlea humeri, from the 



ulnar side. 



(The joint cavity on the anterior surface is not struck at the spot in which it extends furthest 

 upward; the latter corresponds about to the dotted line leading into the fossa coronoidea.) 



In the articulatio cubiti the olecranon ulnae comes to lie in the fossa olecrani humeri 

 when the forearm is extended; when the forearm is flexed, on the contrary, the processus 

 coronoideus ulnae enters the fossa coronoidea humeri and the capitulum radii enters the fossa 

 radialis. During life, however, it is unusual to have the movements of extension and flexion 

 go so far that the projections of the forearm bones mentioned touch the corresponding depressions 

 of the humerus: the movements are checked before this occurs. 



