An 8 year old female presents to the ED after falling 
off the monkey bars at school, complaining of pain in 
her elbow.
     Exam:  There is tenderness over the lateral aspect 
of the elbow and reduced range of motion on flexion, 
supination, and pronation due to pain.  Distally, the 
exam is negative.  Possibly, there is some very mild 
elbow swelling, but this is not obvious.  There are no 
deformities.  Sensation is intact distally.  The radial 
pulse is present at the wrist.  The proximal humerus, 
shoulder, and clavicles are non-tender.  Radiographs of 
the elbow are obtained.

View elbow radiographs.


     These radiographs show a very subtle fracture of 
the radial head at the metaphysis.  This can be seen as 
a slight interruption in the smooth contour of the 
metaphysis.  The anterior fat pad is prominent.  Click on 
[Enlarge] to magnify the image.  The radial head 
fracture is best seen on the AP view on the lateral size 
(left on the screen) of the radial metaphysis as a slight 
irregularity in the cortex.
     An additional oblique view shows the fracture 
somewhat better.

View oblique view.


Discussion & Teaching Points:
     1)  A radial head fracture is not always easy to 
appreciate.  The patient's symptoms may be relatively 
mild.  Flexion and extension of the elbow are frequently 
unremarkable.  Supination and pronation may be more 
limited and/or painful.  There is often tenderness over 
the radial head.  Since radial head fractures tend to 
occur in older individuals, it is unlikely to be mistaken 
for a subluxed radial head as in a nursemaid's elbow; 
however, since it can occur in younger children also, 
this diagnosis should still be considered if the history 
does not suggest a classic pulling injury.
     2)  A sprain injury of the elbow is a diagnostic pitfall 
that should be avoided.  This patient does NOT have an 
elbow sprain.  Occult fractures in the elbow are often 
present and difficult to appreciate radiographically.  A 
normal set of radiographs, even after review by 
radiologists, are not able to totally rule out a fracture.  It 
may be useful to routinely issue a standardized 
instruction sheet explaining this possibility to patients.  
Refer to Case 19 (Swollen Elbow With a Normal X-ray).
     3)  Elbow injuries are fracture prone.  Radiographs 
of this area can be difficult to interpret unless a 
methodical review of the radiographs is performed.  
One of the things that should be carefully inspected is 
the contour of the radial head.  The slope from the 
diaphysis to the metaphysis towards the radial head 
should be gradual and smooth with no sharp angles 
associated with it.  It should NOT look like the end of a 
baseball bat (handle end).

View radiograph in a teenager.  


     This radiograph shows a subtle fracture of the radial 
head.  Note the very slight corner interrupting the 
smooth contour of the radial head metaphysis.  The 
radial head appears to resemble a knob on a pole 
rather than a funnel shape.  The smooth contour of the 
radial head as one proceeds from the epiphysis to the 
metaphysis should be carefully inspected.  Any angles 
noted in this smooth progression may represent a 
fracture, especially if the clinical findings confirm this.  
Enlarging the radiograph or examining the 
radiograph with a magnifying glass may make it 
easier to identify these.

View radiograph in a toddler.

     This radiograph shows a fracture of the radial head.  
Note the sharp angle seen at the radial head 
metaphysis.  This patient presented with symptoms 
similar to a nursemaid's elbow; however, the history did 
not suggest a pulling injury.