Suspect fracture of the scaphoid (navicular) bone in any young adult who has "fallen on an outstretched hand" (classic clue). The physician was concerned about the risk of avascular necrosis because, in some people, the blood supply of the bone is located distally and a fracture would deprive the proximal region of the bone of its aerial nourishment. Osteoahritis is a common complication of scaphoid fractures that do not heal properly. The lunate bone is commonly dislocated in patients who have fallen on an outstretched hand. Median nerve injury is a frequently associated occurrence. The capitate , pisiform , and trapezoid bones of the wrist are less commonly associated with falls on an outstretched hand. Ref: Bednar M.S., Light T.R. (2006). Chapter 10. Hand Surgery. In H.B. Skinner (Ed), CURRENT Diagnosis & Treatment in Ohopedics, 4e.