first of all know that i am fairly new to blender and 3d creation

File: Capture d'écran 2017-03-13 15.14.10.png (798KB, 2880x1674px) Image search: [Google]

798KB, 2880x1674px

first of all know that i am fairly new to blender and 3d creation in general.

i got the mesh of an arm, i've done all the rigging and all but i have one problem.

when i parent the mesh and the armature ( with automatic wheight ) all of the fingers armature deform their respective finger of the mesh correctly, except for the index, when i move the index bones the mesh just stays in place.

Someone knows how to fix it ?

Thanks