AO North America

The Comprehensive Classification of Fractures of Long Bones

12-Humerus Diaphysis

12-Humerus Diaphysis

The subgroups represent a variation within the group and the one illustrated is indicated with red in the text.

12a

A1 Simple fracture, spiral
.1 proximal zone
.2 middle zone
.3 distal zone

A2 Simple fracture, oblique(> or = 30°)
.1 proximal zone
.2 middle zone
.3 distal zone

A3 Simple fracture, transverse (< 30°:)
.1 proximal zone
.2 middle zone
.3 distal zone

12b

B1 Wedge fracture, spiral wedge
.1 proximal zone
.2 middle zone
.3 distal zone

B2 Wedge fracture, bending wedge
.1 proximal zone
.2 middle zone
.3 distal zone

B3 Wedge fracture, fragmented wedge
.1 proximal zone
.2 middle zone
.3 distal zone

12c

C1 Complex fracture, spiral
.1 with two intermediate fragments
.2 with three intermediate fragments
.3 with more than three intermediate fragments

C2 Complex fracture, segmental
.1 with one intermediate segmental fragment
.2 with one intermediate segmental and additional wedge fragment(s)
.3 with two intermediate segmental fragments

C3 Complex fracture, irregular
.1 with two or three intermediate fragments
.2 with limited shattering (< 4 cm)
.3 with extensive shattering (> or = 4 cm)

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