The Hand
Bones
The carpal bones are arranged into two rows of four with the first row of four (closest to the arm) being called the proximal row and the second row of four being called the distal row. The carpal bones are small, and nearly cubic, except for the single pisiform carpal which has only five sides.
The metacarpal bones are the five long bones which together with the carpals make up the palm. These bones can also be considered the “roots” of the digits. These bones are counted from the thumb and numbered as first through fifth metacarpal.
The third set of bones called phalanges are distributed three per finger and two for the thumb. These bones are considered long bones, like the metacarpals. The junctures or joints between these bones are most often called knuckles. They rotate on one axis for the most part and have very limited movement on the other axes.
Muscles
The twelve muscles of the hand are divided into three groups. The first group is called the Thenar Eminence, and these control the thumb. The other special group is called the Hypothenar Eminence, and is dedicated to control of the fourth finger, also called the pinky. The third group of muscles controls the three middle fingers. Their location is the middle of the palm and between the fingers.
Additionally there are twenty muscles which are located in the arm and are responsible for movement(s) of the hand. There are four types of these muscles. They are designated as:
Flexors these muscles flex the wrist and fingers
Extensors these muscles are used to extend the wrist and fingers
These two sets of muscles oppose each other. There are many muscles which operate in this manner of opposing groups.
Supinators these muscles are the muscles that rotate the palm forward.
Pronators these muscles rotate the palm backward.
These operate in opposition to each other just like the Flexors<>Extensors, mentioned above.