Skeleton of Hand
Imagine a hand, palm down, with the thumb positioned to the far right. Start counting the fingers at the thumb as the first digit next the index finger, then the middle finger, the ring finger and lastly the baby finger in order to understand the positioning of the anatomy of the hand bones called the proximal carpals and the distal carpals.
The trapezium is located on the thumb side. It is a distal carpal and has three other bones in a row that are closest to the metacarpals of the hand. They are the trapezoid, the capitate, and the hamate, all are distal carpals. The trapezium bone is the one that controls the movement of the first digit (thumb) and second (index finger) metacarpals.
The scaphoid bone touches the trapezium (distal carpal next to the thumb) and is located in the first row of proximal carpus. It is shaped like a boat and resembles a cashew nut in appearance.
The lunate bone is shaped like a crescent moon and is positioned next to the scaphoid bone.
The other two proximal carpals are the triquetral bone which is has a pyramidal shape and the pisiform which is shaped like a pea, rounded in appearance and about the same size of a pea.
These five bones form a shape similar to a bow. They are the trapezium (next to thumb and a distal carpal), while the scaphoid, the lunate, the triquetral and the pisiform are all proximal carpals. Although they are arranged anatomically in two distinct rows with four bones being in each row which comprise eight bones in the human hand which make up the proximal and distal carpals.
There are five metacarpals which form the palm and twelve bones, called phalanges, which form the fingers.The thumb (first digit) has two phalanges which forms it and it opposes the other four fingers on the hand which have three phalanges on each of them. The carpals (wrist), metacarpals (palm) and phalanges (fingers) are groups of bones that form the hand.