Elbow X-ray

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Four Questions

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Anterior and posterior fat pad signs (in a case of an undisplaced fracture of the radius head which is not visible directly).
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A normal anterior fat pad in a non-fractured arm.
  1. Are the fat pads normal?
    • A visible ant. fat pad is normal but if displaced anteriorly (Sail sign) it is abnormal
    • A visible post. fat pad is always abnormal
    • What if have fat pad displacement but no fracture or displacement is identified?
      • Adults: Treat as radial head fracture
      • Peds: Be certain that neither an undisplaced supracondylar fracture nor a displaced internal epicondyle fracture is overlooked!
  2. Is the radiocapitellar line normal?
    • A line drawn along the longitudinal axis of the radial head and neck should pass through the capitellum
      • If line does not pass through capitellum then dislocation of radial head is probable
    • Whenver there is a fracture of the ulnar shaft must evaluate the radiocapitellar line for possible radial head dislocation (Monteggia fracture dislocation)
    • This rule is always valid on a true lateral film
      • In pediatric cases the AP view may be misleading
  3. Is the anterior humeral line normal?
    • A line drawn along the ant cortex of the humerus will have at leats 1/3 of the capitellum anterior to it
      • If less than 1/3 then strong probability of supracondylar fracture with distal fragment displaced posteriorly
  4. Are the ossification centers normal?
    • CRITOE (Capitellum, Radial head, Internal epicondyle, Trochlea, Olecranon, Lateral Epicondyle)
      • Dislocated elbow may result in avulsion of internal epicondyle
        • Because the trochlea ossifies after the internal epicondyle if you see the trochlea you must find the epicondyle!

See Also

References

  • Accident and Emergency Radiology

Video