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What is Monteggia fracture and explain in detail?
The Monteggia fracture is a fracture of the proximal third of the ulna with dislocation of the proximal head of the radius. It is named after Giovanni Battista Monteggia.

Causes
Mechanisms include:

Fall outstretched hand with the forearm in excessive pronation (hyper-pronation injury).  The ulna fractures in the proximal one-third of the shaft due to extreme dislocation