182 



Joints of the Upper Extremity. 



Membrana interossea 

 antibrachii 



Humerus 



Tendo m. bicipitis 

 (cut through) 



Ulna 



Ligamentum collaterale ulnare 



233. Right elbow joint, articulatio cubiti, 



from the ulnar side. 



Articulatio cubiti (continued) (see also Figs. 232, 234 237). The capsula arti- 

 cularis is tolerably wide and proceeds from the humerus in front and behind in a line convex 

 above; this place of origin lies in the middle in front close above the fossa coronoidea and 

 fossa radialis, behind in the upper part of the fossa olecrani; on the sides it runs distalward 

 from the two epicondyli. On the ulna the capsule is attached in the whole circumference of 

 the incisura semilunaris and incisura radialis beyond the margin of the surface covered with 

 cartilage; to the radius it is fastened around the collum radii, about in the middle between 

 the lower margin of the capitulum and the tuberositas radii. The narrow bulging of the 

 capsule between the incisura radialis ulnae and the circumferentia articularis radii extending 

 distalward is called the recessus sacciformis. 



The powerful, flat, triangular ligamentum collaterale ulnare (0. T. internal lateral 

 ligament) (see also Figs. 232 and 235) is to be mentioned as an especial strengthening liga- 

 ment on the ulnar side; it extends from the epicondylus medialis humeri, its fibres diverging 

 to the ulnar margin of the incisura semilunaris ulnae. 



