The radial head is dislocated and the proximal third of the ulna is fractured. Select the type of fracture or dislocation with which it is most likely to be associated (SELECT 1 INJURY)
**Core Concept**
The question is testing the association between a specific type of fracture or dislocation and another injury in the forearm. The underlying concept is the mechanism of injury and the resulting pattern of fractures or dislocations in the forearm.
**Why the Correct Answer is Right**
A dislocation of the radial head and a fracture of the proximal third of the ulna is a classic association with a Monteggia fracture-dislocation. This occurs when a fall onto a flexed elbow causes a combination of a radial head dislocation and a fracture of the ulna. The ulnar fracture typically occurs at the junction of the proximal and middle thirds of the ulna. The mechanism of injury is due to the forearm being in a pronated position at the time of the fall, resulting in a fracture of the ulna and dislocation of the radial head.
**Why Each Wrong Option is Incorrect**
* **Option A:** A Galleazzi fracture is a type of fracture of the shaft of the ulna with a dislocation of the distal radioulnar joint, not the radial head.
* **Option B:** A both-bone forearm fracture refers to a fracture of both the ulna and radius, but not necessarily associated with a radial head dislocation.
* **Option D:** A Essex-Lopresti injury is a combination of a radial head dislocation, a fracture of the distal ulna, and a disruption of the interosseous membrane.
**Clinical Pearl / High-Yield Fact**
In the emergency department, a patient with a suspected Monteggia fracture-dislocation should have an urgent radiograph of the forearm to assess for this injury, as prompt reduction of the radial head dislocation is essential to prevent complications such as nerve damage and chronic pain.
**Correct Answer: C. A Monteggia fracture-dislocation is a combination of a radial head dislocation and a fracture of the proximal third of the ulna.**