Which fracture is an isolated ulna fracture?

• A. Nightstick
• B. Monteggia
• C. Galeazzi
• D. Barton's

Answer: (A)

An isolated ulna fracture means a break in the ulna without any accompanying fracture of the radius or dislocation at the elbow or wrist joints. This pattern most often comes from a direct blow to the forearm, which is why it’s classically called a nightstick fracture—the impact causes a midshaft ulna fracture while the radius and the joints remain intact.

In contrast, the other patterns involve more complex injuries: a Monteggia fracture-dislocation combines an ulna fracture with dislocation of the radial head at the elbow; a Galeazzi fracture is a distal radius fracture with disruption of the distal radioulnar joint; and a Barton's fracture is an intra-articular fracture of the distal radius with radiocarpal joint involvement. Because those involve the radius or joint dislocations, they are not isolated ulna fractures.