The wrist has three primary joints, allowing it more stability than if it had only one joint. It also provides your wrist and hand with a broad range of movement.
The wrist joints help your wrist move your hand up and down, like when you lift your hand to wave. These joints enable you to bend your wrist forward and backward, side to side, and rotate your hand.
The three main joints of the wrist are the following:
- Radiocarpal Joint - This is where the radius, the thicker forearm bone, joins with the bottom row of wrist bones: the scaphoid, lunate, and triquetrum bones. This joint is mainly on the thumb side of your wrist.
- Ulnocarpal Joint - This is the joint between the ulna, the thinner forearm bone, and the lunate and triquetrum wrist bones. It is found in the pinky finger side of your wrist.
- Distal Radioulnar Joint - This joint is in the wrist but doesn’t include the wrist bones. It bridges the bottom ends of the radius and ulna.
The eight carpal bones which make up the wrist are the following:
- Scaphoid - a long boat-shaped bone under the thumb
- Lunate - a crescent-shaped bone sitting beside the scaphoid
- Trapezium - a rounded-square shaped bone sitting above the scaphoid and under the thumb
- Trapezoid - a bone beside the trapezium that is shaped like a wedge
- Capitate - oval-shaped bone in the middle of the wrist
- Hamate - a bone under the pinky side of the hand
- Triquetrum - a pyramid-shaped bone under the hamate
- Pisiform - a small, round bone on top of the triquetrum
The major soft tissues found in the wrist include:
- Ligaments - Connect the wrist bones to each other and to the hand and forearm bones.
- Tendons - Elastic connective tissue that attaches muscles to bones.
- Bursae - Fluid-filled sacs that reduce friction between tendons and bones.
