You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Fallen fragment sign is a feature of - and explain in detail?
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.