The scaphoid bone is one of the small bones of the wrist, which are known as carpal bones. It is located between the hand and forearm on the radial side (the side with the thumb). It is about the size and shape of a cashew. The radial styloid process is a conical bump located on the radius, a bone of the lower arm. The radial carpal collateral ligament connects the scaphoid bone and the radial styloid process. This ligament prevents the wrist from bending too far to the side, away from the thumb. The scaphoid bone takes a lot of force to break. Nonetheless, it is the most commonly fractured bone of the wrist. Fractures of the scaphoid often occur during sporting activities, when someone falls on their outstretched hand and hyperextends their wrist. Fractures of the scaphoid are usually slow to heal, due to limited blood circulation. Damage to the bone can cause damage to the radial carpal collateral ligament. Improper healing of fractured bones and stretched or torn ligaments is a primary cause of osteoarthritis. Arthritis itself can then cause further deterioration of the ligaments.