Anatomic Location

This is designed by two numbers, one for the bone and one for its segment.

Each bone or group of bones is designated by a number from 1 to 8: Humerus (1), Radius/Ulna (2), Femur (3), Tibia/Fibula (4), Spine (5), Pelvis (6), Hand (7), Foot (8). All the remaining bones are classified under 9: Patella (91.1), Clavicle (91.2), Scapula (91.3), Mandible (92), Facial Bones and Skull (93).

Segments of long bones. Each long bone has 3 segments: the proximal, the diaphyseal, and the distal segment. The malleolar segment is an exception and is classified as the 4th segment of the tibia/fibula (44-).

Rule of the Squares:
The proximal and distal segments of long bones are defined by a Square whose sides are the same length as the widest part of the epiphysis.

Exceptions:
31- The proximal femur is defined by a line which passes transversely through the lower edge of the lesser trochanter.
44- The malleolar fractures are not included in the segment 43-. They are considered as a separate segment.

Assignement:
Before a fracture can be assigned to a segment, one must first determine its center. In a simple fracture the center of the fracture is obvious. In a wedge fracture the center is at the level of the broadest part of the wedge. In a complex fracture the center can only be determined after reduction.
Any fracture associated with a displaced articular component is classified as an articular fracture. If the fracture is associated only with an undisplaced fissure which reaches the joint, it is classified as metaphyseal or diaphyseal depending on where its center is.