Of the bones in the carpus:
A. The scaphoid is the largest boneScapholunate dissociation is followed by flexion of the scaphoid. The capitate is the largest of the carpal bones. 80% of the scaphoid blood supply enters at the waist (hence the predilection to non-union of a proximal pole fracture) and 80% of the scaphoid surface is covered in articular cartilage. The kinetic forces of the carpus produce a tendency for the scaphoid to flex. The scaphoid moves into flexion if it is released from the lunate by laxity or rupture of the scapholunate ligament.