Volume 1, Case 12

Radiographic Examination of the Elbow- The Hourglass Sign
Radiology Cases in Pediatric Emergency Medicine
Volume 1, Case 12
Alson S. Inaba  MD

Exam: Upon presentation to the ED, she prefers to hold her left arm in the extended position with the forearm pronated. She is able to wiggle all fingers and her thumb without any difficulty, and her distal sensation appears to be intact. She has full range of motion about the wrist without any tenderness over the scaphoid bone. The shoulder and clavicle also appear to be nontender. The left elbow region reveals a mild degree of swelling without any overlying lacerations or abrasions. The child cries with attempted supination and pronation of the forearm but there does not seem to be much resistance during passive supination or pronation. She cries a lot when you palpate near the elbow joint and resists flexion of the elbow beyond 90 degrees. Because of the possibility of an elbow fracture you order an AP and lateral view of the elbow.

View elbow radiographs.

X-Ray

Click here for a better picture

Questions:

a)  Do you see any obvious fractures, and if so, where?
b)  What are "fat pads", and what do they signify?
c)  Is an anterior "fat pad" pathologic?
d)  Is a posterior "fat pad" pathologic?
e)  What is the radiologic significance of the anterior humeral line 
	and the radiocapitellar line?
f)  Are these 2 views adequate to rule-out a fracture?  If
     not, then what additional view(s) would you obtain at
     this point?

What is your Diagnosis

Click here for the Case 12 Answers

 Loren Yamamoto, 
      MD, MPH Associate Professor of Pediatrics University of Hawaii John A. Burns 
      School of Medicine loreny@hawaii.edu