Reading Elbow X-rays
Radiocapitellar line, fat pads, and the coronoid you miss.
Aug 31, 2026 · 3 refs
At a glance
The adult elbow series is AP, lateral, and often an external oblique. A true lateral stacks the capitellum and trochlea as circles. The radial head must point at the capitellum on every view — if it does not, the joint is not reduced.
Technique pointers
Lateral
- Concentric circles (capitellum / trochlea)
- Radiocapitellar line
- Coronoid — easy to hide under the radial head
- Anterior and posterior fat pads (occult intra-articular fracture)
AP / oblique
- Ulnohumeral and radiocapitellar joint space even medial to lateral
- Proximal radioulnar joint
- Radial head still aimed at capitellum
Decision-making
A fat pad without an obvious fracture is still a fracture until proven otherwise (radial neck, occult distal humerus). A “simple” dislocation is only simple after you have excluded coronoid and radial head. Recheck NV status before and after reduction; document the stable arc.
High-yield / exam
- Radius to capitellum on all views
- Fat pad = intra-articular blood
- Look specifically at the coronoid
- Pediatric ossification is a different Topic — do not mix the systems
Questions
Ortho Skills (Real Life) and Boards items for this topic are coming.
Your pearl
One line you’d tell a junior at 2am.
References
- 01
Elbow trauma — radiographic evaluation and instability patterns
2015 · Journal of the American Academy of Orthopaedic Surgeons · review
Radiocapitellar alignment and associated fractures define the injury.
- 02
Terrible triad of the elbow — evaluation sequence
2017 · Journal of the American Academy of Orthopaedic Surgeons · review
Dislocation is not cleared until radial head and coronoid are accounted for.
- 03
OTA teaching on elbow radiographic series and fat-pad signs
2018 · Orthopaedic Trauma Association · guideline
True lateral and joint-line checks prevent missed coronoid injuries.
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