Swollen Elbow with a Normal X-Ray
Radiology Cases in Pediatric Emergency Medicine
Volume 1, Case 19
Loren G. Yamamoto, MD, MPH
Kapiolani Medical Center For Women And Children
University of Hawaii John A. Burns School of Medicine
     An 8 year old male presents to the ED complaining 
of pain in his left elbow after falling off a 2 meter high 
wall onto his hand and arm.
     Exam:  The left elbow is obviously swollen.  He is
reluctant to move it due to pain.  He points to the lateral 
region of his elbow as the area of greatest pain.  
Tenderness to the medial elbow is mild.  Palpation of 
the mid and upper humerus is non-tender.  Palpation of 
the mid and distal forearm is non-tender.  His clavicle is 
non-tender.  His wrist is non-tender including the radial 
and ulnar epiphyses.  The carpal bones are non-tender 
and his hand function is good.   AP and lateral 
radiographs of the elbow are obtained.

View elbow radiographs.

     Although these radiographs appear to be normal, 
the patient obviously has something wrong with his 
elbow.  Diagnosing a sprain of the elbow is a pitfall that 
should be avoided.  When the patient has obvious 
clinical findings around the elbow, examine the 
radiographs carefully for a posterior fat pad sign, a 
supracondylar fracture, a radial head fracture, and 
misplaced ossification centers that may represent 
     In this case, none of these are visible on the 
radiographs, which should lead one to be suspicious of 
an occult fracture not radiographically visible.  In this 
case, two oblique views of the elbow were obtained.

View oblique films.

     The first oblique view does not reveal much, but the 
other oblique view shows an obvious fracture of the 
lateral (external) condyle.  This diagnosis makes sense 
based on the patient's physical exam.  This fracture 
typically produces a larger than expected degree of 
     One might consider that this fragment over the 
lateral condyle is the ossification center of the external 
epicondyle (lateral condyle); however, this ossification 
center does not have this appearance.  In addition, this 
ossification center is the last to appear in the elbow.  
The ossification center of the olecranon appears before 
this.  Since the olecranon's ossification center is not 
visible (see lateral view), the external epicondyle will not 
be ossified yet.  The mnemonic CRITOE is useful to 
remember the sequence of appearance of the elbow 
ossification centers (Capitellum, Radial Head, Internal 
epicondyle, Trochlea, Olecranon, and External 
epicondyle).  See Case 11 (Elbow Ossification Centers 
in a Child) for more details.
     In retrospect, this fracture is visible on the AP
view.  Go back and examine the lateral condyle region
of the AP view.  Magnify the view to examine it closely.

View AP and lateral view above:

Discussion & Teaching Points:
     1)  A swollen elbow usually contains a fracture 
injury.  In some instances, a joint effusion (posterior fat 
pad sign or enlarged anterior fat pad sign) can be seen 
in the absence of a visible fracture.  Occult fractures 
may still be present in such cases.  It is prudent to treat 
such an injury as a non-displaced fracture, with a splint, 
sling, and follow-up with a primary care physician or 
orthopedic surgeon.
     2)  When uncertainty exists, careful examination of 
the patient will often help guide your review of the 
radiographs and the need to request special views.
     3)  Occult fractures in the elbow may be difficult to
identify.  Areas that are commonly fractured include the
supracondylar region, the radial head, and the lateral 
     4)  Even with special views, not all fractures are 
radiographically visible.  Other imaging modalities such 
as bone scanning, CT scanning, and MRI scanning 
have all identified fractures in patients with normal 
radiographs.  Normal radiographs are not able to totally 
rule out fractures.  It is often beneficial to advise 
patients of the limitation of radiographs.  In any 
musculoskeletal injury, persistent pain should prompt 
the patient to seek medical care even if their initial set 
of radiographs was normal.  Orthopedic referral, a 
repeat set of radiographs, or an advanced imaging 
modality should be considered in injuries resulting in 
persistent pain.
     5)  It is useful to include a standardized instruction
sheet to patients whenever radiographs are obtained in 
the emergency department.  This instruction sheet 
should explain the possibility of interpretation errors, 
differences of opinion in the radiographic interpretation, 
the limitation of radiographs, and instructions for 
follow-up.  Such an instruction sheet can substantially 
reduce the number of patient complaints regarding 
misinterpreted radiographs and reduce the ED's liability 
potential.  An example of such an instruction sheet 

     1.  The emergency physician has read your X-ray 
as:  Normal elbow (example)
     2.  Large abnormalities requiring urgent care are
generally obvious and, therefore, this is unlikely at this 
point.  An emergency physician can find most of the 
problems on an X-ray, but the emergency physician is 
not a specialist in radiology.
     3.  To be sure, we will have the hospital radiologist
(X-ray specialist) read your X-ray on the morning of the 
next working day (Monday through Saturday).  If there 
is an important difference in the X-ray reading, we will 
try to call you or your doctor, but this doesn't always 
happen.  To double check us, please call your physician 
or the hospital clinic (949-8899) to find out how your 
X-ray is being read by the radiologist.  If you call the 
hospital X-ray department directly, they will not give you 
the reading over the phone since the medical reading is
not understood by most people.  It must be done 
through your doctor.
     4.  When you call your doctor or your doctor's office
nurse, tell him/her that you came to the Emergency 
Department where some X-rays were taken, and you 
were told to call your doctor to double-check the X-ray 
reading with the hospital radiologist.  The most 
common things that are missed on X-ray readings are 
tiny fractures (cracks, chips, or hairlines) and small 
areas of infection (bronchitis, pneumonia, bone 
infection, etc.).
     5.  To be sure that these problems are not there, it is
important that you contact your physician so that you 
will receive the proper care for this condition.
     6.  For injuries, pain that lasts for more than a week 
or pain that doesn't get better after two days could 
mean that you have a hidden broken bone, even if your 
X-rays are normal (X-rays cannot find all broken 
bones).  See your doctor for an examination of the 
area.  Another set of X-rays may be needed.

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Web Page Author:
Loren Yamamoto, MD, MPH
Associate Professor of Pediatrics
University of Hawaii John A. Burns School of Medicine