2001 Rig Layout

These bones are sometimes called the control bones, because
They are controlling more than just the mesh.  They also control hidden bones that
affect the behavior of the different body parts.

thoms controls
Here is a rundown on the basic layout of the animation controls.

moving thoms feet and hands
Hand targets and feet targets move the limbs around.

moving the spine and extremities
hands, toes, back1, back2, shoulders, neck, and head all move their respective body parts.

knees and elbow movement
elbow and knee bones aim the arms and legs in the rightdirection.
elbow and knee bones only move in hinges, more on that later.

hip translation
The hips move everything except the feet, which stay in place

moving the buttbone
The buttbone moves the lower body without moving the upper body.
When your character needs to shift its weight on the feet, or  'boogy' down
with the other characters, this is the bone to do it with. Elvis Presleywouldbe proud

everything bone
The Everything bone moves all of the bones; Controls, mesh bones,everything.  This is useful
in the action window when you dont have access to the 'black' bone of the character,
which is visible only in choreography. The black bone is the origin of the entire model.