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Wednesday, 13 January 2016

image based Q.22 - elbow injury child

Q. The below radiograph of an injured child with elbow region swelling has pain and restricted motion. The black shadow in front of distal humerus depicts which of these signs to call it an occult fracture with subsequent effusion ?



1. Crescent sign
2. Fish tail sign
3. Fat pad sign
4. Arc sign































Answer - 3

The normal fat pads over distal humerus get elevated due to any effusion in the joint or occult underlying fracture and a black shadow/ lucency  is seen in the radiograph either anterior (as seen here - anterior fat pad= coronoid fat pad ) or posterior (posterior fat pad= olecranon fat pad).


Posterior fat pad are more specific for occult  fractures (>70%)


Crescent sign is seen in supracondylar humerus  fracture as the normal capitellum is seen overshadowed by proximal ulna thus formation of a crescent.


Fish tail deformity results from osteonecrosis of trochlea due to various injuries.

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