Authors of section

Editors

Peter Kloen, David Ring

Executive Editors

Peter Trafton, Michael Baumgaertner

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Ulna, extraarticular, multifragmentary (AO/OTA 2U1A3)

Multifragmentary metaphyseal fractures of the ulna are classified as 2U1A3 fractures.

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X-ray taken from Orozco R et al, (1998) Atlas of Internal Fixation. Used with kind permission.
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The radial head can dislocate or subluxate posteriorly with respect to the capitellum (posterior Monteggia lesion). It’s uncommon to have a fracture in this part of the ulna without radial head dislocation and it’s uncommon to have a posterior dislocation of the radial head without fracture of the radial head.

The illustration shows a Jupiter Type B Posterior Monteggia without radial head fracture - an extremely uncommon event.

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