A lateral radiograph of the elbow of a 4-year-old who fell on an outstretched hand shows a line drawn along the anterior cortex of the distal humerus passing through the anterior third of the capitulum instead of its middle. What does this finding indicate?

• A Normal elbow, no further action needed
• B Dislocation of the radial head
• C Posteriorly displaced supracondylar fracture of the humerus ✓
• D Avulsion of the medial epicondyle into the joint

Explanation

On a true lateral film the anterior humeral line should bisect the middle third of the capitulum. Passage through the anterior third means the distal fragment has tilted or shifted posteriorly, the classic finding in an extension type supracondylar fracture, even when the fracture line itself is subtle. Radial head dislocation is assessed by the radio-capitellar line, not this line, and a normal study would show the line traversing the midcapitulum.

Reference: Moore's Clinically Oriented Anatomy, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.