It also includes the end of the arm bones. Your wrist is made up of eight small bones called the carpal bones , or the carpus. These join your hand to the two long bones in your forearm — the radius and ulna. The carpal bones are small square, oval, and triangular bones. The cluster of carpal bones in the wrist make it both strong and flexible. The wrist has three main joints. This makes the wrist more stable than if it had only one joint. It also gives your wrist and hand a wide range of movement.
The wrist joints let your wrist move your hand up and down, like when you lift your hand to wave. These joints allow you to bend your wrist forward and backward, side to side, and to rotate your hand. This is where the radius — the thicker forearm bone — connects with the bottom row of wrist bones: the scaphoid, lunate and triquetrum bones.
This joint is mainly on the thumb side of your wrist. This is the joint between the ulna — the thinner forearm bone — and the lunate and triquetrum wrist bones. This is the pinky finger side of your wrist.
It connects the bottom ends of the radius and ulna. The hand bones between your fingers and wrist are made up of five long bones called metacarpals. They make up the bony part at the back of your hand. Wrist bones, ligaments, tendons, muscles and nerves can be injured or damaged. Common wrist injuries and conditions include:.
Setting your location helps us to show you nearby providers and locations based on your healthcare needs. The scaphoid is a bone in the wrist.
It is part of the first row of wrist bones, but it helps to link the two rows of wrist bones together. Most of the scaphoid is covered with cartilage which contacts five other bones in the wrist and forearm. The part of the scaphoid without cartilage is attached to ligaments and has blood vessels that come from the radial artery. Bones need blood flow to heal.
A broken or fractured scaphoid can have difficulty healing, or may never heal, because of a disruption of blood flow through the scaphoid. An intact scaphoid is important and necessary for proper wrist function because of how it interacts with the other wrist bones. This bone has a crescent shape when seen from the side and its large cartilage surface allows for significant wrist motion. It is uncommon to break the lunate, but the lunate can be involved with dislocations of the wrist and can rub against the ulna if the ulna is too long compared to the radius bone.
This bone adds stability to the wrist, gives the wrist a larger surface to bear weight transmitted from the hand, and makes a joint with other carpal bones including the pisiform. The triquetrum lies between the lunate and pisiform bones on the medial side of the proximal row of carpal bones. Fractures of the triquetrum often occur upon forceful dorsiflexion of the hand such that an avulsion fracture occurs on the dorsal aspect of the bone. The pisiform articulates with the anterior surface of the triquetrum bone, therefore extending anteriorly to form the bump that can be felt at the medial base of the hand.
The pisiform bone forms the ulnar border of the carpal tunnel. In contrast to the other carpal bones, the pisiform is not involved in movements of the wrist. It articulates with four bones; the 1 st and 2 nd metacarpals, the scaphoid and the trapezoid. The trapezium has a distinct tubercle on the palmar surface which projects anteriorly.
It gets its name due to its similarity to the trapezium. The trapezoid is the smallest bone in the distal row of carpal bones.
The trapezoid articulates with four bones; the 2 nd metacarpal, the trapezium, the capitate and the scaphoid bone. The trapezoid is the least commonly fractured carpal bone. The capitate is the largest carpal bone and articulates with five bones; the 3 rd metacarpal, the trapezoid, scaphoid, lunate and hamate.
It articulates with five carpal bones; the 4 th and 5 th metacarpals, the capitate, and the triquetrum. The hamate is easily distinguishable due to its shape and a hook-like process that extends towards the palmar surface.
The hamate bone is the most frequently fractured bone when a golfer hits the surface hard with a golf club on the downswing.
Clinically, this may present with pain and symptoms of ulnar nerve damage ; numbness and weakness of flexion in the 4th and 5th fingers. In a similar fashion to the scaphoid, the hook of the hamate is vulnerable to avascular necrosis due to its poor blood supply. The carpal bones form a U-shaped arrangement which is directed anteriorly. The flexor retinaculum spans this U-shaped area to maintain the alignment of the carpal bones.
The medial side of the base of the arch is formed by the pisiform and hook of the hamate. The lateral side of the base of the arch is formed by the scaphoid and trapezium. The flexor retinaculum attaches laterally to the trapezium and scaphoid bones and medially to the hamate and pisiform bones. Both the carpal bones and the flexor retinaculum form the carpal tunnel — the bones forming the wall and floor and the tendon, the roof.
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