Fallen fragment sign is a feature of -

Ans. is 'a' i.e., Simple bone cyst Simple bone cvst (Soliterv/Unicameral bone cyst)o Simple bone cyst occurs before the age of 20 yearso The most common site is proximal humerus (50%)followed by Proximal femur (25-30%).o Radiological features are : -ConcentricMetaphysealExpansile lucent (lytic)Well defined border with sclerotic marginFallen Fragment sign : - Cortical fragment ofpathological fracture settles in the most dependent portion.Hinged fragment sign : - Sometimes fractured fragment does not separate from adjacent cortex.