The wrist is made up of eight small bones (the carpal bones) and two forearm bones (the radius and ulna). The scaphoid (or navicular) bone is one of the eight carpal bones. It sits on the thumb side of the wrist.
A fracture or injury to the scaphoid most commonly occurs from a fall onto an outstretched hand.
A scaphoid fracture is often described as a “bad sprain” and doesn’t always cause significant pain at the time of injury or significantly limit wrist motion. Scaphoid fractures are often troublesome to heal and difficult to treat. A significant number of these fractures will not heal even with treatment due to poor blood supply of the scaphoid.
Fractures or, in other words, breaks can vary in severity. They can be stable and well aligned or unstable and broken in many places. If not evaluated and treated properly the use of the wrist and hand can be significantly affected.
The best way to treat this is to seek a medical evaluation and get x-rays. Treatment will vary on what x-rays show. Sometimes a CT scan or MRI is needed to better evaluate the fracture, blood supply, or healing potential. A splint or a cast may be used to protect the fracture while it heals. Sometimes surgery is necessary.
Source and for more information: American Academy of Orthopaedic Surgeons (AAOS)