106 



DISSECTION OF THE UPPER LIMB. 



Kinds of 

 motion : 



bending, 



extending. 



Movements. The two interphalangeal joints can be bent and 

 straightened like a hinge. 



Flexion and extension. In flexion, the distal phalanx moves 

 round the proximal in each joint, and the motion is checked by 

 the lateral ligaments and the extensor tendon : in the joint between 

 the middle and the metacarpal phalanx this movement is most 

 extensive. In extension the farther phalanx comes into a line 

 with the nearer one, and the motion is stopped by the anterior 

 ligament and the flexor tendons. 



