Joints of the Upper Extremity. 



191 



Processus 

 styloideus 



242. 



Metacarpal bone and 

 phalanges of the third 



finger of the right 

 hand with ligaments, 



from the radial side. 



- Os metacarpale 



Capsula 

 articularis 



Ligamentum 

 accessorium volare 

 Ligamentum 

 collaterale 



Phalanx I 



Capsula 

 articularis 



Capsula 

 articularis 



._ Ligamentum 

 collaterale 



.. Phalanx II 



.__ Ligamentum 

 collaterale 



Phalanx III 



The articulationes metacarpopha- 

 langeae possess a ligamentum collaterale 

 (0. T. lateral ligament) as a strengthening 

 ligament, one on the radial and one on 

 the ulnar side which extends from the 

 lateral surface of the capitulum ossis meta- 

 carpalis obliquely distalward and volarward 

 to the base of the first phalanx. In addi- 

 tion, a ligamenlum accessorium volare 

 (0. T. transverse metacarpal ligament) with 

 one limb on each side to the capitulum 

 ossis metacarpalis just volarward from the 

 ligamentum collaterale runs arch -like to 

 the volar surface of the joint, broadening 

 as it goes; there the two limbs unite so 

 that the whole ligament resembles a loop ; 

 on the volar surface it is united with the 

 ligamentum capitulorum transversum (see 

 Fig. 241). 



In the formation of the articulationes 

 digitorum ma mis (finger joints) the 

 base of each phalanx II is moveably con- 

 nected with the trochlea of each phalanx I 

 and in the same way the base of each 

 phalanx III with the trochlea of each pha- 

 lanx II. In the first finger (thumb), only 

 one such joint is present; in the second 

 to the fifth finger always two. Loose 

 capsulae articulares connect the margins 

 of the cartilaginous joint surfaces with one 

 another and are strengthened by powerful 

 ligamenta coUateralia (0. T. lateral liga- 

 ments) which run to the radial and ulnar 

 side in a manner entirely analogous to 

 that in the articulationes metacarpo- 

 phalangeae. 



