Question

A 34-year-old woman presents with elbow pain and diminished arm movement following a fall on her outstretched hand. Initial history and physical exam are notable for pain, swelling, and tenderness over the lateral elbow, and inability to fully extend the elbow. Which of the following is indicative of a radial head fracture?

A) Displacement of the radiocapitellar line
B) Posterior fat pad sign
C) Pronator sign
D) Wrist drop

Answer 1

Option A. A radial head fracture can be indicated by displacement of the radiocapitellar line on x-ray. The presence of a posterior fat pad sign or the pronator sign can also suggest this fracture, but they are not specific. Wrist drop is not indicative of a radial head fracture.

Step-by-step explanation:

A radial head fracture can be indicated by displacement of the radiocapitellar line. In a normal elbow x-ray, a line drawn through the center of the radial neck should intersect the capitellum. If this line does not intersect the capitellum or is displaced, it suggests a radial head fracture. The posterior fat pad sign is not specific for a radial head fracture, but it can be seen on x-ray when there is an effusion in the elbow joint. This sign is characterized by a radiolucent stripe of fat visible behind the distal humerus.

The pronator sign is not specific for a radial head fracture either. It refers to pain with passive pronation of the forearm and can be seen in various elbow injuries including radial head fractures. Wrist drop is not indicative of a radial head fracture. It is a symptom that occurs when there is damage to the radial nerve, which can happen in radial head fractures, but it is not a specific sign of this fracture.